Kardiologi Flashcards
0
Q
SAIM – kap 1 – Nævn objektive tegn på hjerte sygdom?
A
1) Cardiac murmurs
2) Rytme forstyrrelser
3) Jugular pulsationer
4) Hjerte forstørrelse
1
Q
Slides - Beskriv blodets vej gennem hjertet?
A
Vena cava, højre atrium, tricuspidalklap, højre ventrikel, pulmonær semilunærklap, lunge, pulmonal-vene, mitralklap, venstre ventrikel, aorta semilunærklap, aorta, kroppen og celler
2
Q
SAIM – kap 1 – Nævn kliniske tegn som kan resultere fra hjertesygdom?
A
1) Syncope
2) Meget svag eller stærk arteriel puls
3) Hoste
4) Respirationsbsvær
5) Motionsintolerance
6) Abdominal distention
7) Cyanosis
Sygdomme der ikke inkluderer hjertet, kan også fremkalde disse tegn.
3
Q
SAIM – kap 1 – Hvordan vil man undersøge nærmere, når kliniske tegn tyder på en cardiovaskulær sygdom?
A
Thoracic radiography
Electrocardiography (ECG)
Echocardiography
4
Q
SAIM – kap 1 – Hvornår sker hjertesvigt?
A
Når hjertet ikke kan opfylde kroppens cirkulatoriske behov tilstrækkeligt, eller kun kan gøre det med en høj venetryk.
5
Q
SAIM – kap 1 – Hvad er skyld i stasen ved højrehjertesvigt, og hvad giver stasen ved venstre hjertesvigt?
A
Højre = Stasen stammer fra systemisk venøs hypertension og de resulterende stigninger i systemisk kapillær tryk.
Venstre= Stasen giver pulmonær venøs hypertension og ødem..
6
Q
SAIM – kap 1 – Hvorfor fås motionsintolerance ved hjerte sygdom eller svigt?
A
1) Utilstrækkeligt cardiac output. Impaired skeletmuksle perfusion under motion relateret til vaskulær og metaboliske ændringer som sker over tid.
2) Øget pulmonær vaskulær tryk og ødem.
3) Akut fald i cardiac output forårsaget af arytmier.
7
Q
SAIM – kap 1 – Hvad karakteriserer det kliniske tegn syncope?
A
Forbigående bevidstløshed associeret med af postural tonus (kollaps) pga utilstrækkelig øxygen eller glukose levering til hjernen.
Syncope kan forveksles med seizure episodes.
Bagben svaghed eller pludselig kollaps.
Lateral recumbency
Stive forben og opisthotonos
Micturition
Vokalisering er alm.
Tonic/clonisk motion, facial fits og defækation er IKKE tegn på syncope!!!!
8
Q
SAIM – kap 1 – Hvordan skelner man mllem syncope anfald, episodisk svaghed og rigtige anfald?
A
En detaljeret beskrivelse af dyrets adfærd eller aktivitet før kollapset, under kollapset og efter kollapset, samt kende til hvilken medicin den har fået.
9
Q
SAIM – kap 1 – Hvordan tester man for at finde årsagen til forbigående svaghed eller syncope?
A
ECG (under afslapning, motion og/eller efter motion eller vagal manøvre)
Complete blood count (CBC)
Serum biochemical analysis (incl elektrolytter og glycose)
Neurologisk eksamination
Thoracic radiographs
Hjerteorms test
Echocardiography
10
Q
SAIM – kap 1 – Hvilke cardiovaskulære årsager giver synope?
A
Typiske=
Forskellige arytmier
Ventrikulær outflow obstruktioner
Cyanotiske congenital hjerte defekter
Acquired sygdomme der fører til dårlig cardiac output (fx dilateret cardiomyopati og alvorlig mitral insufficiens)
Atypiske =
Aktivering af vasodepressor reflekser
Store doser af cardiovaskulære lægemidler (fx vasodilators og diuretika)
11
Q
A
12
Q
SAIM - kap 1 - Hvilke dyr får hoste synkope (cough-drop), og hvad indebærer det?
A
Det forekommer hos nogle hunde med markant venstre arteriel forstørrelse og bronchial kompression, og også hos hunde med primær respiratorisk sygdom.
Akut fald i hjerte fyldning og output under hostet.
Perifer vasodilatation efter hostet.
Øget cerebrospinal væske tryk med intracranial vene kompression.
13
Q
SAIM - kap 1 - Hvad resulterer kongestiv hjerteinsufficiens(CHF) i ?
A
1) Hoste
2) Tachypnø
3) Dyspnø
14
Q
SAIM - kap 1 - Hoste, tachypnø og dyspnø kan associeres med hvilke sygdomme?
A
1) Kongestiv hjerteinsufficiens
2) Pulmonær vaskulær sygdom (hund og kat)
3) Pneumonitis pga hjerteorm (hund og kat)
4) Pleural og pericardiel effusioner er nogengange forbundet med hoste.
Hoste forårsaget af hjerte pumonær ødem hos hunde er blød og fugtig, men lyder noglegange som gagging. Modsat er hoste et usædvanlig tegn på pulmonær ødem hos katte.
Tachypnø der udvikler sig til dyspnø forekommer hos både hund og kat.
15
Q
SAIM - kap 1 - Hvilke sygdomme associeres med hoste?
A
1) Pleural og pericardiel effusioner er nogengange forbundet med hoste.
2) Hoste forårsaget af hjerte pumonær ødem hos hunde er blød og fugtig, men lyder noglegange som gagging. Modsat er hoste et usædvanlig tegn på pulmonær ødem hos katte.
3) Hovedstamme bronchie kompression forårsaget af en alvorlig venstre arteriel forstørrelse kan stimulere hoste (ofte tør eller hacking) hos hunde med kronsik mitral indufficiens, selv uden pulmonær ødem eller kongestion.
4) Hjertebasis tumor
5) Forstørrede hilar lymfeknuder
6) Andre masser der kolliderer med luftvejene kan mekanisk stimulere hoste.
16
Q
SAIM - kap 1 - Hvad ses typisk når respiratoriske tegn er forårsaget af en hjertesygdom?
A
1) Genereliseret cardiomegali
2) Venstre atrie forstørrelse
3) Pulmonær vene kongestion
4) Lunge infiltrater som løsnes med diuretisk terapi
5) Positiv hjerteorms test
17
Q
SAIM - kap 1 - Hvad bruger man til at skelne hjerte fra ikke-hjerte grunde til respiratoriske tegn?
A
Fysisk eksamination
Thorax røntgenbilleder
Echocardiogram (hvis muligt)
Elektrocaridiografi (nogengange)
18
Q
SAIM - kap 1 - Beskriv fremgangsmåden for en hjerteundersøgelse?
A
19
Q
SAIM - kap 1 - Hvad betyder hyperpnø og hvad resulterer det fra?
A
Det betyder forøget dybde af respirationen.
Resulterer fra:
Hypoxæmi
Hyperkapni
Acidose
20
Q
SAIM - kap 1 - Hvilke symptomer ses ved pulmonær ødem (og også andre pulmonære infiltrater)?
A
Øget lungestivhed
Hurtig og overfladisk vejrtrækning (tachypnø) = forsøger at minimere arbejdet med at trække vejret.
Øget hvile respirationsfrekvens er en tidlig indikator på pulmonær ødem når der ikke er primær lungesygdom.
21
Q
SAIM - kap 1 - Hvad er forlænget, besværet inspiration er normalt associeret med ?
A
Øvre luftvejssygdomme (obstruktion)
22
Q
SAIM - kap 1 - Hvad er forlænget ekspiration asssocieret med?
A
Nedre luftvejs obstruktion eller pulmonær infiltrativ sygdom incl ødem.
23
Q
SAIM - kap 1 - Hvordan reagerer dyr med alvorlig kompromitteret ventilation?
A
De kan nægt at lægge sig ned. De står eller sidder med albuerne abducted for at tillade maximal ribbens udvidelse.
De vil ikke ligge i lateral(sideleje) eller dorsal recumbency (orthopnø).
De trækker vejret med åben mund (katte).
Katte vil savle (også hunde) pga de sjældent synker og pupillerne kan være dilaterede pga den forhøjet sympatisk tonus.
24
SAIM - kap 1 - Hvad kan giv forhøjet respirationsfrekvens?
Dyspnø
Fornøjelse (exitement)
Feber
Frygt
Smerte
25
SAIM - kap 1 - Hvordan evaluerer man perifer perfusion?
Tjekker slimhindefarver (Mund + vagina/prepuce) og kapillær genopfyldningstid (CRT) (farve skal komme inden for 2 sek).
Hvis de orale slimhinder er pigmenterede, kan okulær konjunktiva evalueres.
26
SAIM - kap 1 - Hvis slimhindefarven vender tilbage efter senere end 2 sek, hvad er det tegn på?
Dehydrering og andre grunde til nedsat cardiac output pga høj perifer sympatisk tonus og vasokonstriktion.
27
SAIM - kap 1 - Hvad er blege slimhinder tegn på?
Anæmi eller perifer vasokonstriktion.
CRT er normal hos anæmiske dyr dog ikke/undtagen når hypoperfusion er tilstede.
28
SAIM - kap 1 - Hvordan undersøger man polycytæmiske katte og hunde for bevis på differential cyanose?
Farven af de caudale slimhinder skal sammenlignes med farven på de orale membraner.
29
SAIM - kap 1 - Hvis petekkier i slimhinderne opdages hos hunde og katte kan det skyldes?
Blodplade forstyrrelser/trombocytforstyrrelser.
30
SAIM - kap 1 - Hvor detekteres ikterus (gulsot) først?
Orale og okulære slimhinder.
Hvis det opdages skal man undersøge nærmere for hæmolyse eller hepatobiliær sygdom.
31
SAIM - kap 1 - Hvornår ses persisterende jugular vene distention?
Hos patienter med:
1) højresidet CHF (pga højreside hjertefyldnings tryk)
2) ekstern kompression af cranial vena cava
3) jugular vene eller craial vene trombose.
32
SAIM - kap 1 - 1) Hvor højt må jugulare pulsationer gå op af halsen når det er normalt?
2) Hvad er grunden till de normale pulsationer?
1) En tredjedel op af halsen fra brystindløbet.
2) Jugular pulsbølger er relateret til atriekontraktion og fyldning.
33
34
SAIM - kap 1 - Hvornår ses synlige pulsationer (må være over en tredjedel på halsen)?
Hos dyr med:
1) trikuspidal insufficiens (efter den første hjertelys, under ventrikel kontraktion).
2) Tilfælde der forårsager en stiv og hypertrofisk højre ventrikel (lige før første hjertelyd, under atriekontraktion)
3) Arytmier som får atriet til at kontrahere mod lukkede AV klapper (so-called cannon "a" waves).
35
SAIM - kap 1 - Nævn grunde til unormale slimhinde farver?
36
SAIM - kap 1 - Hvad kan skabe en positiv hepatojugular reflux selv uden jugular distension eller pulsationer i hvile.
1) Nedsat højre ventrikel fyldning
2) Reduceret pulmonær blodflow
3) Trikuspidal regurgitation (opstød)
37
SAIM - kap 1 - Hvad mærker man efter ved vurdering af perifere arterielle trykbølger og pulsfrekvensen?
Styrken og regelmæssigheden.
Subjektiv vurdering af pulsstyrken er baseret på forskellen mellem den systoliske og diastoliske arterielle tryk (puls trykket). Når forskellen er stor, føles pulsen stærk.
38
SAIM - kap 1 - 1) Hvad kaldes unormal stærk puls?
2) Hvad kaldes unormal svag puls?
1) Unormal stærk puls kaldes hyperkinetisk.
2) Hypokinetisk. (Tryk forskellen er lille)
39
SAIM - kap 1 - Hvad kan grunden være til mangel på eller svagere puls på den ene side af femur? (man palperer altid begge femorale pulse)
Tromboembolisme
40
SAIM - kap 1 - Hos hvilke dyr er femoral puls svær at palpere?
Katte
41
SAIM - kap 1 - Hvad er grunden til svag puls, stærk puls og meget stærk puls?
42
SAIM - kap 1 - Hvordan vurderer man om der er puls mangel/underskud?
Femoral arterie puls frekvens skal evalueres samtidig med den direkte hjertefrekvens, som måles ved brystvægs palpation eller auskultation. Færre femorale pulse end hjertebank beviser en pulsmangel.
43
SAIM - kap 1 - Hvilke sygdomme kan give puls mangel/underskud?
Forskellige hjerte arytmier pga de får hjertet til at banke før tilstrækkelig ventrikelfyldning er sket.
44
SAIM - kap 1 - Hvor mærkes den stærkeste impuls ved precordiumet?
Under systole over området af venstre apex (lokaliseret ca ved femte intercostalrum nær den costocondrale junction).
Cardiomegali eller en pladsopfyldende masse inden i brystt kan skifte impulset til en unormal lokalisation.
45
SAIM - kap 1 - Hvad kan give nedsat intensitet af det precordiale impuls?
Fedme
Svage hjertekontraktioner
Pericardial effusion (A pericardial effusion is an abnormal amount of fluid between the heart and the pericardium, which is the sac surrounding the heart. )
Intrathorax masser
Pleural effusion
Pneumothorax
46
SAIM - kap 1 - Hvad kan give en stærkere højre precordial impuls?
Normalt er venstre impuls stærkest, men når højre impuls er stærkest skyldes det højre ventrikel hypertrofi eller forskydning af hjertet ind i den højre hemithorax af en masse læsion, lunge atelektase eller bryst deformitet.
47
SAIM - kap 1 - Hvad er et precordieal thrill?
Meget høje hjerte mislyde (murmurs) giver palperbare vibrationer på brystvæggen og dette kaldes precodial thrill. Det føles som en summende følelse på hånden. Det er oftest lokaliseret til området for maximal intensitet af mislyden.
48
SAIM - kap 1 - Hvad kan give unormal væske akkumulering inden i kropshuler eller i subcutis af afhængige områder?
Højresidet CHF.
49
SAIM - kap 1 - Hvordan opdager man effusioner eller subcutane ødemer?
Palpation eller ballottement af abdomen
Palpation af afhængige områder
Perkussion af brystet på det stående dyr.
50
SAIM - kap 1 - Hvad ledsages væskeakkumulering sekundært til højresidig hjertesvigt ofte af?
Unormal jugular vene distension og eller pulsationer, undtagen hvis dyrets cirkulerende blodvolumen er mindsket ved diuretikabrug eller andet.
Hepatomegali og/eller splenomegali kan også ses hos katte og hunde med højresidig hjertesvigt.
51
SAIM - kap 1 - Hvad klassificeres hjertelyde som?
De klassificeres som forbigående lyde (dem af kort varighed) og hjertemislyde (længere lyde der sker under normal stille dele af hjertecyklus).
De beskrives ved frekvens, amplitude af vibrationer (intensitet), varighed og kvalitet.
52
SAIM - kap 1 - Hvordan skal dyret placeres når man lytter på hjertet?
Stående position, så hjertet er i sin normale position.
53
SAIM - kap 1 - Hvad bruges klokken til på stetoskopet?
Det bruges til auskultation af lavere-frekvens lyde som S3 og S4.
54
SAIM - kap 1 - Hvilke hjertelyde er normale og kan høres hos hunde og katte?
S1 (associeret med lukning og spænding af AV klapper og associerede strukturer ved starten af systole).
S2 (associeret med lukning af aorta og pulmonale klapper efter ejection/udslyngning).
De diastoliske lyde (S3 og S4) kan IKKE høres hos normale hunde og katte.
55
SAIM - kap 1 - Hvornår sker systole og diastole?
Systole: Mellem S1 og S2.
Diastole: Efter S2 og indtil næste S1.
56
SAIM - kap 1 - Hvornår sker den precordiale impuls?
Lige efter S1 (systole).
57
SAIM - kap 1 - Hvornår sker den arterielle puls?
Mellem S1 og S2.
58
SAIM - kap 1 - Hvad kan en høj S1 (første hjertelyd) skyldes?
Hunde og katte med en tynd brystvæg, høj sympatisk tonus, tachycardi, systemisk arteriel hypertension eller forkortet PR intervaller.
59
SAIM - kap 1 - Hvad kan en dæmpet Sq skyldes?
Fedme, pericardial effucion, diafragma hernia, dilateret cardiomyopati, hypovolæmi/dårlig vntrikkel fyldning eller pleural effusion.
60
SAIM - kap 1 - Hvad øger intensiteten af S2?
Det øges af pulmonær hypertension fx ved hjerteorms sygdom, en congenital shunt med Eisenmnger's fysiologi eller cor pulmonale.
61
SAIM - kap 1 - Hvordan kan hjerte arymiter påvirke hjertelyde?
De giver variation i intensiteten eller endda mangel på hjertelyde.
62
SAIM - kap 1 - Hvorfor kan NORMAL fysiologisk opsplitning af S2 høres hos nogle hunde?
Pga variation i slagvolumen under respirationscyklus. Under inspiration forårsager øget venøs return til højre ventrikel forsinket lukning af den pulmonære klap, mens reduceret fyldning af den venstre ventrikel accelererer aorta lukning.
63
SAIM - kap 1 - Hvorfor kan PATOLOGISK fysiologisk opsplitning af S2 høres hos nogle hunde?
Det kan resultere forsinket centrikel aktivering eller forlænget højre ventrikel ejektion sekundær til ventrikel premature beats, højre bundle branch block , en ventrikel eller atrie septum defekt eller pulmonær hypertension.
64
SAIM - kap 1 - Hvad betyder en galloprytme?
Når S3 eller S4 lyd kan høres lyder hjertet som en galloperende hest. Tilstedeværelsen eller mangel på en lydhør S3 eller S4 har dog INTET at gøre med hjertets rytme (Start at hjerteaktivering og intracaridac konduktionsprocessen).
S3 og S4 høres bedst med klokken da de er af lavere frekvens end S1 og S2.
65
SAIM - kap 1 - Hvad betyder en summations gallop?
Når både S3 og S4 hjertelyde er tilstede kan de være superimposed (overlejret), hvilket kaldes en summations gallop.
66
SAIM - kap 1 - beskriv hjertecyklus diagrammet?
C a r d i a c cycle diagram depicting relationships among great vessel, ventricular a n d atrial pressures, ventricular volume, heart sounds, and electrical activation. AP, Aortic pressure; ECG, electrocardiogram; IC, isovolumic contraction; IR, isovolumic relaxation; LVP, left ventricular pressure; LAP, left atrial pressure; LVV, left ventricular volume.
Fig. 1-10 correlates the hemodynamic
events of the cardiac cycle with the E C G and timing of the heart sounds. It is important to understand these events and identify the timing of systole (between S1 and S2) and diastole (after S2 until the next S1) in the animal. The precordial impulse occurs just after S1 (systole), and the arterial pulse between S1 and S2.
67
SAIM - kap 1 - Forklar om S3?
S3 kendes også som S3 gallop eller ventrikulær gallop. Den er associeret med en lav-frekvens vibration ved slutningen af den hurtige ventrikulære fyldningsfase.
A n audible S3 in the dog or
cat usually indicates ventricular dilation with myocardial
failure. The extra sound can be fairly loud or very subtle andis heard best over the cardiac apex. It may be the only aus¬cultable abnormality in an animal with dilated cardiomyopathy.An S3 gallop may also be audible in dogs with advanced valvular heart disease and congestive failure.
68
SAIM - kap 1 - Hvad kan man høre i et dyr med dilateret cardiomyopati?
S3 hjertelyden kan være det eneste auskultative abnormalitet man kan høre.
69
SAIM - kap 1 - Hos hvilke dyr kan man høre en S3 hjertelyd?
Man kan (may) høre det ved dilateret cardiomyopati, og hos hunde med avanceret valvulær hjertesygdom og kongestiv svigt (congestive failure).
70
SAIM - kap 1 - Forklar om S4 hjertelyden?
The S4 gallop, also called an atrial or presystolic gallop, is associated with low-frequency vibrations induced by blood flow into the ventricles during atrial contraction (just after the P wave of the ECG). A n audible S4 in the dog or cat is usually associated with increased ventricular stiffness and hypertrophy, as with hypertrophic cardiomyopathy or hyperthyroidism in cats. A transient S4 gallop of unknown significance is sometimes heard in stressed or anemic cats.
71
SAIM - kap 1 - Hvis en kat eller hund har en lydhør S4, hvad kan dyret så fejle?
Øget ventrikelulær stivhed og hypertrofi, som ved hypertrofisk cardiomyopati eller hyperthyroidisme hos katte.
72
SAIM - kap 1 - Hvornår hører man systoliske klik?
Systolic clicks are mid-to-late systolic sounds that are usually heard best over the mitral valve area. These sounds have been associated with degenerative valvular disease (endocardiosis), mitral valve prolapse, and congenital mitral dysplasia; a concurrent mitral insufficiency murmur may be present.
.
73
SAIM - kap 1 - Hvornår hører man mitral klik?
In dogs with degenerative valvular disease, a mitral click may be the first abnormal sound noted, with a murmur developing over time.
74
SAIM - kap 1 - Hvad hører man ved auskulatation af et dyr med valvulær pulmonær stenose?
A n early systolic, high-pitched ejection sound at the
left base may occur in animals with valvular pulmonic stenosis or other diseases that cause dilation of a great artery. The sound is thought to arise from either the sudden checking of a fused pulmonic valve or the rapid filling of a dilated vessel during ejection.
75
SAIM - kap 1 - Hvordan beskrives hjertemislyde?
Cardiac murmurs are described by their timing within the
cardiac cycle (systolic or diastolic, or portions thereof),
intensity, PMI on the precordium, radiation over the chest
wall, quality, and pitch.
Murmur intensity is arbitrarily graded on a I to VI
scale (Table 1-1). The PMI is usually indicated by the hemi¬ thorax (right or left) and intercostal space or valve area where it is located, or by the terms apex or base. Because murmurs can radiate extensively, the entire thorax, thoracic inlet, and carotid artery areas should be auscultated. The pitch and quality of a murmur relate to its frequency and subjective assessment. "Noisy" or "harsh" murmurs contain mixed frequencies. "Musical" murmurs are of essentially one frequency with its overtones.
76
SAIM - kap 1 - Hvornår forekommer systoliske hjertemislyde?
Systolic murmurs can occur in early
(protosystolic), middle (mesosystolic), or late (telesystolic)
systole or throughout systole (holosystolic).
77
SAIM - kap 1 - Hvornår forekommer diastoliske hjertemislyde?
Diastolic murmurs generally occur in early diastole (protodiastolic) or throughout diastole (holodiastolic). Murmurs at the very end of diastole are termed presystolic.
78
SAIM - kap 1 - hvornår forekommer kontinuerlige hjertemislyde?
Continuous murmurs begin in systole and extend through S2 into all or part of diastole.
79
SAIM - kap 1 - Beskriv de forskellige hjertemislyde?
1) A holosystolic (plateau-shaped)
murmur begins at the time of S1 and is of fairly uniform
intensity throughout systole. Loud holosystolic murmurs
may mask the S1 and S2 sounds. **AV valve insufficiency and interventricular septal defects** commonly cause this type of murmur because turbulent blood flour occurs throughout ventricular systole.
2) A crescendo-decrescendo or diamondshaped murmur starts softly, builds intensity in midsystole, and then diminishes; S1 and S2 can usually be heard clearly before and after the murmur. This type is also called an ejection murmur because it occurs during blood ejection, usually because of **ventricular outflow obstruction.**
3) A decrescendo murmur tapers from its initial intensity over time; it may occur in systole or diastole.
4) Continuous (machinery) murmurs occur throughout systole and diastole.
80
SAIM - kap 1 - hvilke systoliske hjertemislyde findes der?
Systolic murmurs can be decrescendo,
holosystolic (plateau-shaped), or ejection (crescendo-
decrescendo) in configuration.
81
SAIM - kap 1 - Forklar om funktionelle hjertemislyde?
Hvor høres de?
Hvordan lyder de?
Hvad kan de skyldes?
Functional murmurs usually are heard best over the left
heartbase. They are usually soft to moderate in intensity and of decrescendo (or crescendo-decrescendo) configuration. Functional murmurs may have no apparent cardiovascular cause (e.g., "innocent" puppy murmurs) or can result from an altered physiologic state (physiologic murmurs). Innocent puppy murmurs generally disappear by the time the animal is approximately 6 months of age. Physiologic murmurs have been associated with anemia, fever, high sympathetic tone, hyperthyroidism, marked bradycardia, peripheral arteriovenous fistulae, hypoproteinemia, and athletic hearts. Aortic dilation (e.g., with hypertension) and dynamic right ventricular outflow obstruction are other conditions associated with systolic murmurs in cats.
82
SAIM - kap 1 - forklar om billedet?
FIG 1-12
The usual point of maximal intensity (PMI) and configuration for murmurs typical of various
congenital and acquired causes are depicted on left (A) and right (B) chest walls. AS, aortic (valvular) stenosis; MVI, mitral valve insufficiency; PDA, patent ductus arteriosus; PS, pulmonic stenosis; SAS, subaortic stenosis; TVI, tricuspid valve insufficiency; VSD, ventricular septal defect. (From Bonagura JD, Berkwitt L: Cardiovascular and pulmonary disorders. In Fenner W , editor: Quick reference to veterinary medicine, ed 2, Philadelphia, 1991, JB Lippincott.)
83
SAIM - kap 1 - Forklar om mitral insufficiens hjertemislyde?
The murmur of mitral insufficiency is heard best at the
left apex, in the area of the mitral valve. It radiates well dorsally and often to the left base and right chest wall. Mitral insufficiency characteristically causes a plateau-shaped murmur (holosystolic timing), but in its early stages the murmur may be protosystolic, tapering to a decrescendo configuration. Occasionally this murmur has a musical or "whoop-like" quality. With degenerative mitral valve disease, murmur intensity is related to disease severity.
84
SAIM - kap 1 - Forklar om systoliske ejektions hjertemislyd?
Hvor høres de?
Hvad skyldes de?
Hvilke findes der?
Systolic ejection murmurs are most often heard at the left
base and are caused by ventricular outflow obstruction,
usually from a fixed narrowing (e.g., subaortic or pulmonic valve stenosis) or dynamic muscular obstruction. Ejection murmurs become louder as cardiac output or contractile strength increases.
Der findes subaorta stenose hjertemislyd, blød nonpatologisk systolisk ejections hjertemislyd og pulmonal stenose hjertemislyd.
85
SAIM - kap 1 - Forklar om subaorta stenose hjertemislyd?
Det er en systolisk ejektions hjertemislyd.
The subaortic stenosis murmur is heard
well at the low left base and also at the right base because the murmur radiates up the aortic arch, which curves toward the right. This murmur also radiates up the carotid arteries and occasionally can be heard on the calvarium.
86
SAIM - kap 1 - Forklar om bløde nonpatologiske systoliske ejections hjertemislyde?
Det er en systolisk ejection hjertemislyd.
Soft (grade I-II/VI), nonpathologic systolic ejection (physiologic) murmurs are common in sight hounds and certain other large breeds; these can be related to a large stroke volume (relative aortic stenosis), as well as breed-related left ventricular outflow tract characteristics.
87
SAIM - Forklar om pulmonal stenose hjertemislyde?
Det er systoliske ejection hjertemislyde.
The murmur of pulmonic stenosis is best heard high at the left base. Relative pulmonic stenosis occurs with greatly increased flow through a structurally normal valve (e.g., with a large left-to-right shunting atrial or ventricular septal defect).
88
SAIM - kap 1 - Hvilke hjertemislyde hører man på højre side af hjertet?
Most murmurs heard on the right chest wall are holosystolic, plateau-shaped murmurs, except for the subaortic stenosis murmur (above).
The tricuspid insufficiency murmur is loudest at the right apex over the tricuspid valve. Its pitch or quality may be noticeably different from a concurrent mitral insufficiency murmur, and it often is accompanied by jugular pulsations.
Ventricular septal defects also cause holosystolic
murmurs. The PMI is usually at the right sternal
border, reflecting the direction of the intracardiac shunt. A
large ventricular septal defect may also cause the murmur of relative pulmonic stenosis.
89
SAIM - kap 1 - Er diastoliske hjertemislyde almindelige hos hunde og katte?
Hvad skyldes de?
Nej.
Aortic insufficiency from bacterial endocarditis
is the most common cause, although congenital malformation or degenerative aortic valve disease occasionally occurs.
These diastolic murmurs begin at the time of S2 and are
heard best at the **left base**. They are decrescendo in configuration and extend a variable time into diastole, depending on the pressure difference between the associated great vessel and ventricle. Some aortic insufficiency murmurs have a musical quality.
90
91
SAIM - Forklar om kontinuerlige hjertemislyde?
Hvordan forløber de?
Hvad skyldes de?
Hvor er mislyden højest?
Hvad kan de forveksles med ?
Continuous murmurs. As implied by the name, continuous (machinery) murmurs occur throughout the
cardiac cycle.
They indicate that a substantial pressure
gradient exists continuously between two connecting areas (vessels). The murmur is not interrupted at the time of S2; instead, its intensity is often greater at that time. The murmur becomes softer toward the end of diastole, and at slow heart rates it can become inaudible.
Patent ductus arteriosus (PDA) is by far the most common cause of a continuous murmur.
The PDA murmur is loudest high at the left base above the pulmonic valve area; it tends to radiate cranially, ventrally, and to the right. The systolic component is usually louder and heard well all over the chest. The diastolic component is more localized to the left base in many cases. The diastolic component (and the correct diagnosis) may be missed i f only the cardiac apical area is auscultated.
Continuous murmurs can be confused with concurrent
systolic ejection and diastolic decrescendo murmurs.
92
SAIM - kap 1 - Hvad kan kontinuerlige hjertemislyde forveksles med ?
**Samtidige systoliske ejektioner og diastoliske decrescendo hjertemislyde.. **
But
with these so-called "to-and-fro" murmurs (frem og tilbagegående), the ejection (systolic) component tapers (tilspidses) in late systole and the S2 can be heard as a distinct sound. The most common cause of toand- fro murmurs is the combination of subaortic stenosis with aortic insufficiency. Rarely, stenosis and insufficiency of the pulmonic valve cause this type of murmur.
Likewise,
both **holosystolic and diastolic decrescendo murmurs** occur occasionally (e.g., with a ventricular septal defect and aortic insufficiency from loss of aortic root support). This also is not considered a true "continuous" murmur.
93
SAIM - kap 2 - Hvad tjekker man med hjerte-radiografi?
Thoracic radiographs are important for assessing overall
heart size and shape, pulmonary vessels, and lung parenchyma, as well as surrounding structures. Both lateral and dorsoventral (DV) or ventrodorsal (VD) views should be obtained.
94
SAIM - kap 2 - Hvordan ser hjertet ud ved et VD (ventrodorsal) view på røntgen fremfor et DV view?
For example, the heart tends to look more elongated on the VD view in comparison with that on the DV view.
In general, better definition of the hilar area and caudal pulmonary arteries is obtained using the D V view.
95
SAIM - kap 2 - Hvordan og hvornår er det bedst at foretag røntgen af hjertet?
High kilovoltage peak (kVp)
and low milliampere (mA) radiographic technique is recommended for better resolution among soft tissue structures. Exposure is ideally made at the time of peak inspiration. On expiration, the lungs appear denser, the heart is relatively larger, the diaphragm may overlap the caudal heart border, and pulmonary vessels are poorly delineated
Use of exposure times short enough to minimize respiratory motion and proper, straight (not obliquely tilted) patient positioning are mportant for accurate interpretation of cardiac shape and size and pulmonary parenchyma.
96
SAIM - kap 2 - Hvad tjekker man først ved røntgenbilleder?
The radiographs should be examined systematically,
beginning with assessment of the technique, patient positioning, presence of artifacts, and phase of respiration during exposure.
97
SAIM - kap 2 - Hvilken betydning har hundes brystformation for røntenbilleder af hjertet?
Chest conformation should be considered when
evaluating cardiac size and shape in dogs because normal cardiac appearance may vary from breed to breed. The cardiac shadow in dogs with round or barrel-shaped chests has greater sternal contact on lateral view and an oval shape on D V or V D view. In contrast, the heart has an upright, elongated appearance on lateral view and a small, almost circular shape on D V or V D view in narrow- and deepchested dogs.
98
SAIM - kap 2 - Hvad skal man huske når man foretager røntgen af hvalpes hjerter?
The cardiac shadow in puppies normally appears slightly
large relative to thoracic size compared with that of adult
dogs.
99
SAIM - kap 2 - Hvad bruger man vertebral heart score til (VHS)?
The vertebral heart score (VHS) can be used as a means
of quantifying the presence and degree of cardiomegaly in dogs and cats, because there is good correlation between body length and heart size regardless of chest conformation.
A VHS between 8.5 to 10.5 vertebrae is considered
normal for most breeds.
100
SAIM - kap 2 - Hvad er forskellen ml. røntgen af hunde og kattehjerter set lateralt fra?
The cardiac silhouette on lateral view in cats is aligned
more parallel to the sternum than in dogs; this parallel positioning may be accentuated in old cats.
101
SAIM - kap 2 - Hvad skal man tænke på når man røntgenfotograferer kattehjerter?
Størrelse?
Radiographic positioning
can influence the relative size, shape, and position of
the heart because the feline thorax is so flexible.
On lateral view the normal cat heart is less than or equal to two intercostal spaces (ICS) in width and less than 70% of the height of the thorax.
On DV view the heart is normally no more
than one half the width of the thorax. Measurement of VHS is useful in cats also. From lateral radiographs in cats, mean VHS in normal cats is 7.5 vertebrae (range 6.7 to 8.1 v).
102
SAIM - kap 2 - Hvad skal man tænke på når man røntgenfotograferer kattekillinger?
In kittens, as in puppies,
the relative size of the heart compared with that of the thorax is larger than in adults because of smaller lung volume.
103
SAIM - kap 2 - Hvad kan give en unormal lille hjerteskygge på røntgen?
```
An abnormally small heart shadow results from reduced
venous return (e.g., from shock or hypovolemia). The apex appears more pointed and may be elevated from the sternum.
```
104
SAIM - kap 2 - Hvad kan en forstørrelse af hjerteskyggen på røntgenbilleder skyldes?
Generalized enlargement of the heart shadow on plain thoracic radiographs may indicate **true cardiomegaly** or **pericardial distention.**
With cardiac enlargement, the contours of different chambers are usually still evident, although massive right ventricular (RV) and atrial (RA) dilation can cause a round cardiac silhouette.
Fluid, fat, or viscera within the pericardium tends to obliterate these contours and create a globoid heart shadow.
105
SAIM - kap 2 - Hvlke hjertekamre forstørres ved mitral insufficens?
Mitral insufficiency leads to left ventricular (D7) and left atrial (LA) enlargement;
106
SAIM - kap 2 - Hvilke hjertekamre forstørres ved pulmonær stenose?
Pulmonic stenosis causes RV enlargement, a
main pulmonary artery bulge, and often RA dilation.
107
SAIM - kap 2 - Hvordan ser en forstørret venstre atrium ud på røntgen?
The LA is the most dorsocaudal chamber of the heart. A n enlarged LA bulges dorsally and caudally on
lateral view. There is elevation of the left and possibly right mainstem bronchi; compression of the left mainstem bronchus occurs in patients with severe LA enlargement.
On DV or VD view, the mainstem bronchi are
pushed laterally and curve slightly around a markedly
enlarged LA (sometimes referred to as the "bowed-legged cowboy sign"). A bulge in the 2- to 3-o'clock position of the cardiac silhouette is common in cats and dogs with concurrent left auricular enlargement.
108
SAIM - kap 2 - Hvad påvirker venstre atriums størrelse?
L A size is influenced by the pressure or volume
load imposed, as well as the length of time the overload has been present.
109
SAIM - kap 2 - Hvordan ser venstre ventrikel forstørrelse ud på røntgen?
LV enlargement is manifested on lateral view by a taller
cardiac silhouette with elevation of the carina and caudal
vena cava. The caudal heart border becomes convex, but
cardiac apical sternal contact is maintained. On D V / VD
view, rounding and enlargement occur in the 2- to 5-o'clock position.
Some cats with hypertrophic cardiomyopathy maintain the apical point; concurrent atrial enlargement creates the classic "valentine-shaped" heart.
110
SAIm - kap 2 - Hvad giver generaliseret forstørrelse af hjerteskyggen på røntgen?
Generalized Enlargement of the Cardiac Shadow:
Dilated cardiomyopathy
Mitral and tricuspid insufficiency
Pericardial effusion
Peritoneopericardial diaphragmatic hernia
Tricuspid dysplasia
Ventricular or atrial septal defect
Patent ductus arteriosus
111
SAIM - kap 2 - Hvad giver forstørret venstre atrie på røntgen?
Left Atrial Enlargement:
Early mitral insufficiency
Hypertrophic cardiomyopathy
Early dilated cardiomyopathy (especially Doberman Pinschers)
(Sub)aortic stenosis
112
SAIm - kap 2 - Hvad giver både forstørret venstre atrie og ventrikel på røntgen?
Left Atrial and Ventricular Enlargement:
Dilated cardiomyopathy
Hypertrophic cardiomyopathy
Mitral insufficiency
Aortic insufficiency
Ventricular septal defect
Patent ductus arteriosus
(Sub)aortic stenosis
Systemic hypertension
Hyperthyroidism
113
SAIM - kap 2 - Hvad giver både højre atrie og ventrikelforstørrelse?
Right Atrial and Ventricular Enlargement:
Advanced heartworm disease
Chronic, severe pulmonary disease
Tricuspid insufficiency
Pulmonic stenosis
Tetralogy of Fallot
Atrial septal defect
Pulmonary hypertension (with or without reversed shunting
congenital defect)
Mass lesion within the right heart
114
SAIM - kap 2 - Hvad ses ved højre atrium forstørrelse på røntgen?
RA enlargement causes a bulge of the cranial heart border and widening of the cardiac silhouette on lateral view. Tracheal elevation may occur over the cranial portion of the heart shadow.
Bulging of the cardiac shadow on DV/VD view occurs in the 9- to 11-o'clock position. The RA is largely superimposed (overlejret) over the RV; although differentiation from RV enlargement is difficult, concurrent enlargement of both chambers is common.
115
SAIM - kap 2 - Hvad ses ved højre ventrikel forstørrelse på røntgen?
Right Ventricle
RV enlargement (dilation or hypertrophy) usually causes
increased convexity of the cranioventral heart border and
elevation of the trachea over the cranial heart border on
lateral view.
With severe RV enlargement and relatively
normal left heart size, the apex is elevated from the sternum. The carina and caudal vena cava are also elevated. The degree of sternal contact of the heart shadow is not, by itself, a reliable sign of RV enlargement because of breed variation in chest conformation.
On D V / V D view, the heart tends to take on a reverse-D configuration, especially without concurrent left-sided enlargement. The apex may be shifted leftward, and the right heart border bulges to the right.
116
SAIM - kap 2 - Hvad får aorta og main pulmonær arterien til at dilatere?
Kronisk arteriel hypertension eller øget turbulens (post-stenotisk dilatation).
Subaortisk stenise giver dilatation af ascending aorta. Widening and increased opacity of the dorsocranial heart shadow may be observed.
Patent ductus arteriosus causes a localized
dilation in the descending aorta just caudal to the arch,
which is where the ductus exits; this "ductus bump" is seen on D V or V D view. A prominent aortic arch is more common in cats than dogs.
117
SAIM - kap 2 - Hvad får main pulmonary trunk til at dilatere?
Severe dilation of the main pulmonary trunk (usually
associated with pulmonic stenosis or pulmonary hypertension) can be seen as a bulge superimposed over the trachea on lateral radiograph.
O n D V view in the dog, main pulmonary trunk enlargement causes a bulge in the 1- to 2-o'clock position. In the cat the main pulmonary trunk is slightly more medial and is usually obscured within the mediastinum.
118
SAIM - Hvordan påvirkes vena cava caudalis (CaCV) ved forstørrelse af ventriklerne i hjertet?
Hvad skyldes det?
The CaVC-cardiac junction
is pushed dorsally with enlargement of either ventricle. Persistent widening of the CaVC could indicate right ventricular failure, cardiac tamponade, pericardial constriction, or other obstruction to right heart inflow.
119
SAIM - kap 2 - .Hvad kan en tynd vena cava caudalis skyldes?
A thin CaVC can indicate hypovolemia, poor venous
return, or pulmonary overinflation.
120
SAIM - hvilke 4 pulmonære vaskulære mønstre er normalt beskrevet?
1) Overcirkulation
2) Undercirkulation
3) Prominent pulmonære arterier
4) Prominente pumonære vener
121
SAIM - kap 2 - Hvad skyldes overcirkulation som er en af de 4 pulmonære vaskulære mønstre?
An overcirculation pattern occurs when the lungs are
hyperperfused, as in left-to-right shunts, overhydration, and other hyperdynamic states. Pulmonary arteries and veins are both prominent; the increased perfusion also generally increases lung opacity.
122
SAIM - kap 2 - Hvad skyldes undercirkulation som er en af de 4 pulmonære vaskulære mønstre?
Pulmonary undercirculation is characterized
by thin pulmonary arteries and veins, along with
increased pulmonary lucency. Severe dehydration, hypovolemia, obstruction to right ventricular inflow, right-sided congestive heart failure, and tetralogy of Fallot can cause this pattern. Some animals with pulmonic stenosis appear to have pulmonary undercirculation. Overinflation of the lungs or overexposure of radiographs also minimizes the appearance of pulmonary vessels.
123
SAIM - kap 2 - Hvad skyldesprominente pulmonære arterier som er en af de 4 pulmonære vaskulære mønstre?
Pulmonary arteries larger than their accompanying veins
indicate pulmonary arterial hypertension. The pulmonary
arteries become dilated, tortuous, and blunted, and visualization of the terminal portions is lost. Heartworm disease often causes this pulmonary vascular pattern, as well as patchy to diffuse interstitial pulmonary infiltrates.
124
SAIM - kap 2 - Hvad skyldes prominente pulmonære vener som er en af de 4 pulmonære vaskulære mønstre?
Prominent pulmonary veins are a sign of pulmonary
venous congestion, usually from left-sided congestive heart failure. On lateral view, the cranial lobar veins are larger and denser than their accompanying arteries and may sag ven¬ trally. Dilated, tortuous pulmonary veins may be seen entering the dorsocaudal aspect of the enlarged LA i n dogs and cats with chronic pulmonary venous hypertension. But pulmonary venous dilation is not always visualized i n patients with left-sided heart failure. In cats with acute cardiogenic pulmonary edema, enlargement of both pulmonary veins and arteries can be seen.
125
SAIM - kap 2 - Hvad kan øge pulmonær skyggen (dvs gøre skyggen mere mørk) på røntgen?
Pulmonary interstitial fluid accumulation (pulmonær ødem) increases pulmonary opacity.
The air-filled bronchi appear as lucent, branching lines surrounded by fluid density (air bronchograms).
126
SAIM - kap 2 - Hvor lokaliseres cardiogen pulmonær ødem hos hunde?
Cardiogenic pulmonar edema in dogs is classically located in dorsal and perihilar areas and is often bilaterally symmetric. Nevertheless, some dogs develop an asymmetric or concurrent ventral distribution of cardiogenic edema.
127
SAIM - kap 2 - Hvor lokaliseres cardiogen pulmonær ødem hos katte?
The distribution of cardiogenic
edema in cats is usually uneven and patchy. The infiltrates are either distributed throughout the lung fields or concentrated in the middle zones.
128
SAIM - kap 2 - Hvad påvirker de interstitielle infiltraters alvorlighed?
Both the radiographic technique
and the phase of respiration influence the apparent severity of interstitial infiltrates.
129
SAIM - kap 2 - hvad repræsenterer EKG grafisk?
```
The electrocardiogram (ECG) graphically represents the
electrical depolarization and repolarization of cardiac muscle.
```
130
SAIM - kap 2 - Hvad kan et EKG fortælle om hjertet?
The E C G provides information on heart rate, rhythm, and
intracardiac conduction; it may also suggest the presence of specific chamber enlargement, myocardial disease, ischemia, pericardial disease, certain electrolyte imbalances, and some drug toxicities.
131
SAIM - kap 2 - Hvad kan et EKG alene IKKE fortælle om hjertet?
But the ECG alone cannot be used to make a
diagnosis of congestive heart failure, assess the strength (or even presence) of cardiac contractions, or predict whether the animal will survive an anesthetic or surgical procedure.
132
SAIM - kap 2 - Forklar om EKG'ets QRS kompleks?
The E C G waveforms, P-QRS-T, are generated
as heart muscle is depolarized and then repolarized. The QRS complex, as a representation of ventricular muscle electrical activation, may not necessarily have each individual Q, R, or S wave components (or variations thereof). The configuration of the QRS complex depends on the lead being recorded as well as the pattern of intraventricular conduction.
133
SAIM - kap 2 - Hvad er en ledningsakse?
The orientation of a lead with respect to the heart is called the lead axis.
Each lead has direction and polarity.
134
SAIM - kap 2 - Hvordan fungerer ledningerne i et EKG?
Each lead has a positive and a negative
pole or direction. A positive deflection will be recorded in a lead i f the cardiac activation wave travels toward the positive pole (electrode) of that lead. If the wave of depolarization travels away from the positive pole, a negative deflection will be recorded in that E C G lead.
135
SAIM - kap 2 - Hvordan fungerer bipolære EKG ledninger?
Both bipolar and unipolar
ECG leads are used clinically. A bipolar lead records electrical potential differences between two electrodes on the body surface; the lead axis is oriented between these two points.
136
SAIM - kap 2 - Hvordan fungerer unipolære EKG ledninger?
(Augmented) unipolar leads have a recording electrode
(positive) on the body surface. The negative pole of
the unipolar leads is formed by "Wilson's central terminal"
(V), which is an average of all other electrodes and is analogous
to zero.
137
SAIM - kap 2 - Hvordan placeres en hund når den skal have foretaget en EKG?
Routine ECG recording is usually done with the animal
placed on a nonconducting surface in right lateral recumbency. The proximal limbs are parallel to each other and perpendicular to the torso.
However, if only heart rate and rhythm
are desired, any recording position can be used.
The animal is gently restrained in position to minimize movement artifacts.
Holding the mouth shut to discourage panting or placing a hand on the chest of a trembling animal may be helpful.
138
SAIM - kap 2 - Hvordan placeres ledningerne ved et EKG?
Front limb
electrodes are placed at the elbows or slightly below, not
touching the chest wall or each other. Rear limb electrodes are placed at the stifles or hocks. With alligator clip or button/plate electrodes, copious E C G paste or (less ideally) alcohol is used to ensure good contact. Communication between two electrodes via a bridge of paste or alcohol or by physical contact should be avoided.
139
SAIM - kap 2 - Hvad er standard kalibreringen der bruges ved EKG?
Standard [1 cm = 1 mV]
The calibration used during the recording must be known to accurately measure waveform amplitude.
A calibration square wave (1 m V amplitude)
The paper speed and lead(s) recorded also must be evident for interpretation.
140
SAIM - Hvordan analyserer man en EKG?
First the paper speed, lead(s) used, and calibration
are identified. Then the heart rate, heart rhythm, and M EA are determined. Finally, individual waveforms are measured.
Individual waveforms and intervals are usually measured
using lead II. Amplitudes are recorded in millivolts and
durations in seconds.
At 50 mm/sec paper speed, each small box equals 0.02 seconds. A deflection from baseline (up or down) of 10 small boxes (1 cm) equals 1 m V at standard calibration.
For example, endurance-trained dogs can have E C G measurements that exceed the "normal" range, probably reflecting the training effects on heart size. Such changes i n nontraineddogs suggest pathologic cardiac enlargement.
141
SAIM - kap 2 - Hvad karakteriserer regelmæssig sinusrytme ved EKG?
Regular sinus rhythm is characterized by less than 10% variation in the timing of the QRS to QRS (or R to R) intervals.
Normally the QRS complexes are narrow and upright in leads II and aVF. However, an intraventricular conduction disturbance or ventricular enlargement pattern may cause them to be wide or abnormally shaped.
142
SAIM - kap 2 - Hvad karakteriserer sinusarytmi på EKG?
Sinus arrhythmia is characterized by cyclic slowing and
speeding of the sinus rate. This is usually associated with
respiration; the sinus rate tends to increase on inspiration
and decrease with expiration as a result of fluctuations in
vagal tone.
There may also be a cyclic change in P-wave
configuration ("wandering pacemaker"), with the P waves
becoming taller and spiked during inspiration and flatter in expiration.
Sinus arrhythmia is a **common and normal**
rhythm variation in dogs. It occurs in resting cats but is not often seen clinically.
Pronounced sinus arrhythmia is associated with **chronic pulmonary disease i**n some dogs.
143
SAIM - kap 2 - Hvordan definerer man et sinusstop på en EKG?
Sinus arrest is absence of sinus activity lasting at least
twice as long as the animal's longest expected QRS to QRS interval. A n escape complex usually interrupts the resulting pause i f sinus activity does not resume in time. Long pauses can cause fainting or weakness. Sinus arrest cannot be differentiated with certainty from sinoatrial (SA) block by the surface ECG.
144
SAIM - kap 2 - Hvad betyder ektopiske rytmer?
Impulses originating from outside the sinus node (ectopic
impulses) are abnormal and create an arrhythmia (dysrhythmia).
Ectopic impulses are described on the basis of their general site of origin (atrial, junctional, supraventricular, ventricular) and their timing (Fig. 2-9). Timing refers to whether the impulse occurs earlier than the next expected sinus impulse (premature) or after a longer pause (late or escape). Escape complexes represent activation of a subsidiary pacemaker and function as a rescue mechanism for the heart. Premature ectopic impulses (complexes) occur singly or in multiples; groups of three or more constitute an episode of tachycardia.
145
SAIM - kap 2 - Hvad er et bigeminal mønster?
Det er noget ektopiske rytmer kan gøre. When one premature complex follows each normal QRS, a bigeminal pattern exists; the origin of the premature complexes determines whether the rhythm is described as atrial or ventricular bigeminy.
146
SLIDES - Hvilke kompensatoriske mekanismer findes der for hjertet?
Arterio-venøs iltdifferens
Slagvolumen
Hjertefrekvens
147
Slides - Hvilke hunde får Mitralklapdysplasi?
Bullterrier. \> 80 % afficerede hunde
148
Slides - Nævn kongenitale hjertesygdomme hos familiedyr?
## Footnote
:
Kongenitale:
**Aortastenose/subaortalstenose
Persisterende ductus arteriosus
botalli
Pulmonalstenose
Ventrikelseptumdefekt**
Fallots tetrade
Atrioventrikulære dysplasier
Atrieseptumdefekt
Persisterende højre aortabue
149
Slides - Nævn erhvervede hjertesygdomme hos familiedyr?
Erhvervede:
**1. Myxomatøs mitral valvulær sygdom
2. Dilateret kardiomyopati
3. Hypertrofisk kardiomyopati**
4. Restriktiv kardiomyopati
5. Arytmogen højre ventrikeldysplasi
6. Myokarditis
7. Endokarditis
**8. Aytmier – supra- og ventrikulære**
9. Neoplasier
**10. Cor pulmonale**
11. Perikardiesygdomme
12. Systemisk arteriel hypertension
13. Tromboembolisme
14. Hyperthyreoidisme
15. Parasitære sygdomme f.eks.
angiostrongylose
150
Slides - Hvilke hunde og katteracer har man screeningprogrammer for i DK ifht hjertelidelser?
Echo-group in Denmark
• Newfoundland
• Dogue de Bordeaux
• Cavalier King Charles Sp.
• Boxer
• Irish wolfhound, Great Dane,
Bullterrier
• Voluntary basis
• Cat breeds
• Maine coon, Norwegian forrest
cat, British shorthair ……
• Pawpeds.com
151
SAIM - kap 2 - Hvor udspringer supraventrikulære premature/umodne komplekser fra?
Hvordan ser de ud på EKG'en?
Supraventricular premature complexes are impulses that
originate above the atrioventricular (AV) node, either in the atria or the AV junctional area.
If the specific origin of the ectopic complex(es) is unclear, the more general term supraventricular premature complex (or supraventricular tachycardia) is used.
Because they are conducted into and through the ventricles via the normal conduction pathway, their QRS configuration is normal (unless an intraventricular conduction disturbance is also present).
152
SAIM - kap 2 - Hvad "forårsager" en P-bølge på EKG?
Premature complexes arising within the atria are usually preceded by an abnormal P wave (positive, negative, or biphasic configuration) called a P' wave.
153
SAIM - kap 2 - Hvad forårsager fysiologisk AV blok?
If an ectopic P' wave occurs
before the AV node has completely repolarized, the impulse may not be conducted into the ventricles (an example of physiologic AV block).
154
SAIM - kap 2 - Hvad giver en negativ P bølge på EKG'et?
Although P' waves usually do not
precede junctional complexes, retrograde conduction into
the atria sometimes causes a negative P' wave to follow, be superimposed on, or even precede the associated QRS complex.
155
SAIM - kap 2 - Hvad kan en nonkompensatorisk pause på EKG'et skyldes?
Supraventricular premature complexes that also depolarize the sinus node reset the sinus rhythm and create a "noncompensatory pause" (i.e., the interval between the sinus complexes preceding and following the premature complex is less than that of three consecutive sinus complexes).
156
SAIM - kap 2 - Hvad kan starte en reentrant supraventrikulær tachycardi (SVT?)? (supraventrikulærte tachycardier)
Hvordan ser EKG'et ud?
A premature supraventricular
or ventricular impulse can initiate reentrant supraventricular tachycardia (SVT).
During episodes of reentrant
SVT in animals with ventricular preexcitation, the PR interval usually normalizes or is prolonged, and retrograde P' waves may be evident. The QRS complexes are of normal configuration unless a simultaneous intraventricular conduction disturbance is present.
157
SAIM - kap 2 - Hvad forårsager atriel tachycardi?
Atrial tachycardia is caused by rapid discharge of an
abnormal atrial focus or by atrial reentry (repetitive activation caused by conduction of the electrical impulse around an abnormal circuit within the atria).
Atrial tachycardia can be paroxysmal or sustained. It is
usually a regular rhythm unless the rate is too fast for the AV node to conduct every impulse, in which case physiologic AV block and irregular ventricular activation result.
158
SAIM - kap 2 - Hvad kan give en bundle branch block pattern på EKG'et?
(Atrie tachycardi) Sometimes the impulses traverse the AV node but are delayed within the ventricular conduction system, causing a bundle branch block pattern on the ECG.
(Supraventrikulær tachycardi) In some cases, the premature impulse is conducted slowly (prolonged P 'Q interval) or with a bundle branch block pattern.
(Atrieflimren) Minor variation in QRS complex amplitude is common, however, and intermittent or sustained bundle branch blocks can occur.
(intraventrikulære ledningsforstyrrelser) Left bundle branch block (LBBB) is usually related to clinically relevant underlying left ventricular disease. The left anterior fascicular block (LAFB) pattern is common in cats with hypertrophic cardiomyopathy.
159
SAIM - kap 2 - Hvad er atrieflagren (atrial flutter) og hvordan ser det ud på EKG'et?
Atrial flutter is caused by a very rapid (usually greater than 400 impulses/min) wave of electrical activation regularly cycling through the atria. The ventricular response may be irregular or regular, depending on the pattern of AV conduction. The E C G baseline consists of "sawtooth" flutter waves that represent the fast, recurrent atrial activation. Atrial flutter is not a stable rhythm; it often degenerates into atrial fibrillation or may convert back to sinus rhythm.
160
SAIM - kap 2 - Hvad er atrieflimren og hvordan ser det ud på EKG'et?
This common arrhythmia is characterized by rapid and
chaotic electrical activation within the atria. There are no P waves on the E C G because there is no uniform atrial depolarization wave. Rather, the baseline usually shows irregular undulations (fibrillation waves).Lack of organized electrical activity **prevents meaningful atrial contraction. **The AV node, being bombarded by chaotic electrical impulses, conducts as many as possible to the ventricles. Ultimately the (ventricular) heart rate is determined by AV conduction velocity and recovery time, which are influenced by prevailing autonomic tone.
Atrial fibrillation (AF) causes an irregular heart rhythm that is often quite rapid
The QRS complexes are usually normal in configuration because intraventricular conduction pathway is usually normal.
161
SAIM - kap 2 - Hvad giver atrieflimren?
A F tends to be a consequence of severe
atrial disease and enlargement in dogs and cats; it is usually preceded by intermittent atrial tachyarrhythmias and perhaps atrial flutter. AF sometimes occurs spontaneously in giant breed dogs without evidence of underlying heart disease ("lone" AF). The heart rate can be normal in these dogs.
162
SAIM - kap 2 - Hvad er ventrikulær umodne komplekser og hvordan ser de ud på EKG'er?
Ventricular premature complexes (VPCs or PVCs) originate below the AV node and do not activate ventricular muscle via the normal ventricular conduction pathway. Therefore their QRS configuration differs from the animal's sinus complexes.
Ventricular ectopic complexes are usually wider
than sinus-origin complexes because of slower intramuscular conduction. Because VPCs usually are not conducted backward through the AV node into the atria, the sinus rate continues undisturbed; thus the V P C is followed by a "compensatory pause" in the sinus rhythm.
When the configuration
of multiple VPCs or ventricular tachycardia is consistent
in an animal, the complexes are described as being uniform, unifocal, or monomorphic. When the VPCs occurring in an individual have differing configurations, they are said to be multiform or polymorphic. Increased electrical instability may accompany multiform VPCs or tachycardia.
163
SAIM - kap 2 - Hvad er ventrikulær tachycardi og hvordan ser det ud på EKG'et?
Ventricular tachycardia consists of a series of VPCs (usually at a rate greater than 100 beats/min). The RR interval is most often regular, although some variation can occur. Noncon¬ ducted sinus P waves may be superimposed on or between the ventricular complexes, although they are unrelated to the VPCs because the AV node and/or ventricles are in the refractory period (physiologic AV dissociation).
164
SAIM - kap 2 - Hvad betyder capture beat?
The term capture beat refers to the successful conduction of a sinus P wave into the ventricles uninterrupted by another V P C (i.e., the sinus node has "recaptured" the ventricles).
165
SAIM - kap 2 - Hvad er fusionskomplekser, og hvornår sker de? EKG
If the normal ventricular activation sequence is interrupted by a VPC, a "fusion" complex can result. A fusion complex represents a melding of the normal QRS configuration and that of the VPC (see Fig. 2-10, E). Fusion complexes are often observed at the onset or end of a paroxysm (anfald) of ventricular tachycardia; they are preceded by a P wave and shortened PR interval.
Identification of P waves (whether conducted or not) or fusion complexes helps in differentiating ventricular tachycardia from SVT with abnormal (aberrant) intraventricular conduction.
166
SAIM - kap 2 - hvad er polymorf ventrikulær tachycardi og hvordan ser det ud på EKG'et?
Polymorphic ventricular tachycardia is characterized by
QRS complexes that vary in size, polarity, and often rate;
sometimes the QRS configuration appears as i f it were rotating around the isoelectric baseline. Torsades de pointes is a specific form of polymorphic ventricular tachycardia associated with Q-T interval prolongation.
167
SAIM - kap 2 - hvad er accelerert ventrikulær
Also called idioventricular tachycardia, accelerated ventricular rhythm is a ventricular-origin rhythm with a rate of about 60 to 100 beats/min in the dog (perhaps somewhat faster in the cat). Because the rate is slower than true ventricular tachycardia, it is usually a less serious rhythm disturbance.
An accelerated ventricular rhythm may appear intermittently during sinus arrhythmia, as the sinus rate decreases; the ventricular rhythm is often suppressed as the sinus rate increases. This is common in dogs recovering from motor vehicle trauma. Often this rhythm disturbance has no deleterious effects, although it could progress to ventricular tachycardia, especially in clinically unstable patients.
168
SAIM - kap 2 - Hvad er ventrikelflimren og hvordan ser det ud på EKG?
Ventricular fibrillation is a lethal rhythm that is characterized by multiple reentrant circuits causing chaotic electrica activity in the ventricles; the E C G consists of an irregularly undulating baseline (Fig. 2-12). The ventricles cannot function as a pump because coordinated mechanical activity cannot occur in the presence of incoordinated electrical activation. Ventricular flutter, which appears as rapid sine-wave activity on the ECG, may precede fibrillation. "Course" ventricular fibrillation (VF) has larger E C G oscillations than "fine"VF.
169
SAIM - kap 2 - Hvad er Escape komplekser?
Ventricular asystole is the absence of ventricular electrical (and mechanical) activity. Escape complexes and escape rhythms are a protective mechanism. An escape complex occurs after a pause in the dominant (usually sinus) rhythm.
Escape activity originates from automatic cells within the atria, the AV junction, or the ventricles.
It is important to differentiate escape from premature complexes. Escape activity should never be suppressed with antiarrhythmic drugs.
170
SAIM - kap 2 - Forklar om ledningsforstyrrelser i hjertet?
Abnormal impulse conduction within the atrium can occur
at several sites.
1) Wit h sinoatrial (SA) block, impulse transmission from the SA node to the atrial muscle is prevented. Although this cannot reliably be differentiated from sinus arrest on the ECG, with SA block the interval between P waves is a multiple of the normal P to P interval. A n atrial, junctional, or ventricular escape rhythm should take over after prolonged sinus arrest or block.
Atrial standstill occurs when diseased atrial muscle prevents normal electrical and mechanical function, regardless of sinus node activity; consequently, a junctional or ventricular escape rhythm results and P waves are not seen. Because hyperkalemia interferes with normal atrial function, it can mimic atrial standstill.
171
SAIM - kap 2 - Hvad kan give ledningsforstyrrelser i AV knuden?
Abnormalities of AV conduction can occur from:
1) excessive vagal tone
2) drugs (e.g., digoxin, xylazine, medetomidine,
verapamil, and anesthetic agents)
3) organic disease of the AV node and/or intraventricular conduction system.
172
SAIM - kap 2 - Hvilke tre kategorier af AV knude ledningsforstyrrelser findes der?
Threecategories of AV conduction disturbances are commonly described (Fig. 2-13).
1) First-degree AV block, the **mildest**, occurs when conduction from the atria into the ventricles is **prolonged**. All impulses are conducted, but the **PR interval is longer than norma**l.
2) Second-degree AV block is characterized by **intermittent AV conduction;** **some P waves are not followed by a QRS complex**. When many P waves are not conducted, the patient has high-grade second-degree heart block. **There are two subtypes of second-degree AV block**.
- **Mobitz type I** (Wenckebach) is characterized by progressive
prolongation of the PR interval until a nonconducted P wave occurs; it is frequently associated with **disorders within the AV node itself and/or high vagal tone**.
**- Mobitz type II** is characterized by **uniform PR intervals preceding the blocked impulse** and is thought to be more often associated with disease lower in the AV conduction system (e.g., bundle of His or major bundle branches).
- A n alternative classification of second-degree AV block based on QRS configuration has been described. Patients with **type A second-degree block** have a **normal, narrow QRS configuration**; those with **type B second-degree block** have a **wide or abnormal QRS configuration**, which suggests diffuse disease lower in the ventricular conduction system. Mobitz type I AV block usually is type A, whereas Mobitz type II frequently is type B. **Supraventricular or ventricular escape complexes** are common during long pauses in ventricular activation.
3) Third-degree or **complete AV block** is complete failure of AV conduction; no sinus (or supraventricular) impulses are conducted into the ventricles. **Although a regular sinus rhythm or sinus arrhythmia is often evident, the P waves are not related to the QRS complexes**, which result from a (usually) r**egular ventricular escape rhythm**.
173
SAIM - kap 2 - Hvornår sker intraventrikulære ledningsforstyrrelser?
Abnormal (aberrant) ventricular conduction occurs in association with slowed or blocked impulse transmission in a major bundle branch or ventricular region. The right bundle branch or the left anterior or posterior fascicles of the left bundle branch can be affected singly or in combination. A block in all three major branches results in third-degree (complete) heart block. Activation of the myocardium served by the blocked pathway occurs relatively slowly, from myocyte to myocyte; therefore the QRS complexes appear wide and abnormal.
Right bundle branch block (RBBB) is sometimes identified in otherwise normal dogs and cats, although it can occur from disease or distention of the right ventricle.
Left bundle branch block (LBBB) is usually related to clinically relevant underlying left ventricular disease.
The left anterior fascicular block (LAFB) pattern is common in cats with hypertrophic cardiomyopathy.
174
SAIM - kap 2 - Hvad menes med ventrikulær præexcitation og hvorfor sker det? Hvordan ser det ud på EKG?
```
Early activation (preexcitation) of part of the ventricular
myocardium can occur when there is an accessory conduction pathway that bypasses the normal slow-conducting AV nodal pathway. Several types of preexcitation and accessory pathways have been described. Most cause a shortened PR interval.
```
Wolff-Parkinson-White (WPW) preexcitation is
also characterized by early widening and slurring of the QRS by a so-called delta wave (Fig. 2-15). This pattern occurs because the accessory pathway (Kent's bundle) lies outside the AV node (extranodal) and allows early depolarization (represented by the delta wave) of a part of the ventricle distant to where normal ventricular activation begins.
The presence of the WPW pattern on ECG in conjunction with reentrant supraventricular tachycardia that causes clinical signs **characterizes the W PW syndrome.**
Other accessory pathways connect the atria or dorsal areas of the AV node directly to the bundle of His. These cause a short PR interval without early QRS widening.
175
SAIM - kap 2 - Hvad er det farlige ved ventrikulær præexitation?
Preexcitation can be intermittent or concealed (not evident on ECG). The danger with preexcitation is that a **reentrant supraventricular tachycardia** can occur using the accessory pathway and AV node (also called **AV reciprocating tachycardia**).
Usually the tachycardia impulses travel into the ventricles via the AV node (antegrade or orthodromic conduction) and then back to the atria via the accessory pathway, but sometimes the direction is reversed. Rapid AV reciprocating tachycardia can cause weakness, syncope, congestive heart failure, and death.
176
SAIM - kap 2 - Hvad beskriver mean electrical axis (MEA)?
The mean electrical axis (MEA) describes the average direction of the ventricular depolarization process in the frontal plane. It represents the summation of the various instantaneous vectors that occur from the beginning until the end of ventricular muscle activation. Major intraventricular conduction disturbances and/or ventricular enlargement patterns can shift the average direction of ventricular activation and therefore the MEA. Only the six frontal plane leads are used to determine MEA.
177
SAIM - kap 2 - Hvad skyldes ændringer i EKG kurver?
Changes in the ECG waveforms can suggest enlargement or abnormal conduction within a particular cardiac chamber. However, enlargement does not always produce these changes.
178
SAIM - kap 2 - Hvordan ser EKG ud ved LA forstørrelse?
A widened P wave has been associated with LA
enlargement (p mitrale); sometimes the P wave is notched
as well as wide.
179
SAIM - kap 2 - Hvordan ser EKG ud ved RA forstørrelse?
Tall, spiked P waves (p pulmonale) can
accompany RA enlargement.
180
SAIM - kap 2 - Hvordan ser EKG ud ved atrie forstørrelse?
With atrial enlargement, the usually obscure atrial repolarization (Ta) wave may be evident as a baseline shift in the opposite direction of the P wave.
181
SAIM - kap 2 - Hvordan ser EKG ud ved RV forstørrelse?
A right-axis deviation and an S wave in lead I are strong
criteria for RV enlargement (or RBBB). Other ECG changes can usually be found as well. Three or more of the criteria listed in Box 2-4 are generally present when right ventricular enlargement exists. RV enlargement (dilation or hypertrophy) is usually pronounced if it is evident on the ECG because LV activation forces are normally so dominant.
Box 2-4:
Right Ventricular Enlargement:
Right-axis deviation
S wave present in lead I
S wave in V2-3 larger than R wave or \>0.8 mV
Q-S (W shape) in V10
Positive T wave in lead V10 (except Chihuahua breed)
Deep S wave in leads II, III, and aVF
182
SAIM - kap 2 - Hvordan ser EKG ud ved LV forstørrelse?
LV dilation and eccentric hypertrophy (see Chapter 3) often increase R-wave voltage in the caudal leads (II and aVF) and widen the QRS. LV concentric hypertrophy inconsistently produces a left-axis deviation.
Box 2-4:
Left Ventricular Hypertrophy:
Left-axis deviation
R wave in lead I taller than R wave in leads II or aVF
No S wave in lead I
183
SAIM - kap 2 - Hvordan ser EKG ud ved ledningsforsinkelse?
Conduction block in the major ventricular conduction
pathways disturbs the normal activation process and alters
QRS configuration. Electrical activation of ventricular
muscle regions served by a diseased bundle branch occurs late and progresses slowly. This widens the QRS complex and shifts the terminal QRS orientation toward the area of delayed activation.
184
SAIM - kap 2 - Hvis amplituden af QRS-komplekserne bliver mindre, hvad kan det skyldes?
Small-voltage QRS complexes sometimes occur. Causes of reduced QRS amplitude include pleural or pericardial effusions, obesity, intrathoracic mass lesions, hypovolemia, and hypothyroidism. Small complexes are occasionally seen in dogs without identifiable abnormalities.
185
SAIM - kap 2 - Hvad er ST-segmentet på et EKG?
The ST segment extends from the end of the QRS complex (also called the J-point) to the onset of the T wave. In dogs and cats this segment tends to slope into the following T-wave, so clear demarcation is uncommon.
186
SAIM - kap 2 - Hvad kan ændringer i ST-segmentet på et EKG skyldes, og hvordan ser det ud på EKG'et?
Abnormal **elevation** or **depression** of the J point and ST
segment in leads I, II, or aVF may be significant and can be caused by **ischemia** and other types of **myocardial injury**.
Atrial enlargement or tachycardia can cause pseudode¬
pression of the ST segment because of prominent Ta waves.
Other secondary causes of ST segment deviation include
ventricular hypertrophy, slowed conduction, and some drugs (e.g., digoxin).
187
SAIM - kap 2 - Hvad repræsenterer T-kurven på EKG'et og hvilke ændringer kan ses i denne og hvad skyldes det?
The T wave represents ventricular muscle repolarization;
it may be positive, negative, or biphasic in normal cats and
dogs. Changes in size, shape, or polarity from previous
recordings in a given animal are probably clinically important.
Abnormalities of the T wave can be primary (i.e., not
related to the depolarization process) or secondary (i.e.,
related to abnormalities of ventricular depolarization). Secondary ST-T changes tend to be in the opposite direction of the main QRS deflection.
188
SAIM - kap 2 - Hvad repræsenterer QT-intervallet på EKG'et og hvilke ændringer kan ses i denne og hvad skyldes det?
The QT interval represents the total time of ventricular activation and repolarization. This interval varies inversely with average heart rate; faster rates have a shorter QT interval. Autonomic nervous tone, various drugs, and electrolyte disorders influence the duration of the QT interval (see Box 2-6). Inappropriate prolongation of the QT interval may facilitate development of serious reentrant arrhythmias when underlying nonuniformity in ventricular repolarization exists. Prediction equations for expected QT duration have been derived for normal dogs and cats.
189
SAIM - kap 2 - Hvilke lægemidler kan ændre hjerterytme og/eller ledningsevne?
Digoxin, antiarrhythmic agents, and anesthetic drugs often
alter heart rhythm and/or conduction either by their direct
electrophysiologic effects or by affecting autonomic tone
190
SAIM - kap 2 - Hvordan på virker kalium hjertet og hvordan ses hypokalæmi og hyperkalæmi på et EKG?
Potassium has marked and complex influences on cardiac
electrophysiology.
**Hypokalemia** can increase spontaneous
automaticity of cardiac cells, as well as nonuniformly slow
repolarization and conduction; these effects predispose to
both supraventricular and ventricular arrhythmias.
**Hypokalemia** can cause progressive ST segment depression, reduced T-wave amplitude, and QT interval prolongation. Severe hypokalemia can also increase QRS and P-wave amplitudes and durations. In addition, hypokalemia exacerbates digoxin toxicity and reduces the effectiveness of class I antiarrhythmic antiarrhythmic agents (see Chapter 4). Hypernatremia and alkalosis worsen the effects of hypokalemia on the heart.
Moderate **hyperkalemia** actually has an antiarrhythmic
effect by reducing automaticity and enhancing uniformity
and speed of repolarization. However, rapid or severe
increases in serum potassium concentration are arrhythmogenic primarily because they slow conduction velocity and shorten the refractory period.
The sinus node is relatively resistant to the effects of hyperkalemia and continues to function, although often at a slower rate. Despite progressive atrial muscle unresponsiveness, specialized fibers transmit sinus impulses to the ventricles, producing a "sinoventricular" rhythm. The characteristic "tented" T-wave appearance may be more apparent in some leads than in others and may be of small amplitude.
Fig. 2-18 illustrates the ECG effects of severe
hyperkalemia and the response to therapy in a dog with
**Addison's disease.**
191
SAIM - kap 2 - Hvilke tilstande påvirker EKG ændringerne forårsaget af hyperkalæmi?
Hypocalcemia, hyponatremia, and acidosis
accentuate the ECG changes caused by hyperkalemia, whereas hypercalcemia and hypernatremia tend to counteract them.
192
SAIM - kap 2 - Hvilken elektrolyt forstyrrelse laver markante EKG ændringer?
Kalium. Det er sjældent andre elektrolytter gør det.
193
SAIM – kap 2 – Hvad er forskellen ml. artifakter og arytmier på en EKG?
Other artifacts are sometimes confused with arrhythmias; however, artifacts do not disturb the underlying cardiac rhythm. Conversely, ectopic complexes often disrupt the underlying rhythm and are followed by a T wave. Careful examination for these characteristics usually allows differentiation between intermittent artifacts and arrhythmias.
194
SAIM - kap 2 - hvordan virker Holter monitorering? (Ambulatorisk EKG)
Holter monitoring allows the continuous recording of
cardiac electrical activity during normal daily activities (except swimming), strenuous exercise, and sleep. This is useful for detecting and quantifying intermittent cardiac arrhythmias and therefore helps identify cardiac causes of syncope and episodic weakness. Holter monitoring is also used to assess the efficacy of antiarrhythmic drug therapy and to screen for arrhythmias associated with cardiomyopathy or other diseases.
During the recording period, the animal's activities
are noted in a patient diary for later correlation with
simultaneous E C G events.
195
SAIM - kap 2 - Er hjerte rytmen den samme for hhv. hunde og katte hele dagen igennem?
NEJ!
Wide variation in heart rate is seen throughout the day
in normal animals. In dogs maximum heart rates of up to
300 beats/min have been recorded with excitement or activity. Episodes of bradycardia (\<50 beats/min) are common, especially during quiet periods and sleep. Sinus arrhythmia, sinus pauses (sometimes for more than 5 seconds), and occasional second-degree AV block are apparently common in dogs, especially at times when mean heart rate is lower. In normal cats heart rates also vary widely over 24 hours (e.g. from ~70 to ~290 beats/minute. Regular sinus rhythm predominates
i n normal cats, and sinus arrhythmia is evident
at slower heart rates. Ventricular premature complexes occur only sporadically i n normal dogs and cats; their prevalence likely increases only slightly with age.
196
SAIM - kap 2 - Hvad bruger man event recording til ? (Ambulatorisk EKG)
Event recorders are used most often to determine whether episodic weakness or syncope is caused by a cardiac arrhythmia.
When an episode is observed, the owner activates the
recorder, which then stores the ECG from a predetermined
time frame (e.g., from 30 seconds before activation to 30 seconds after) for later retrieval and analysis.
197
SAIM - kap 2 - Hvad påvirker cariationen i tid mellem på hinanden følgende hjerteslag.
Phasic fluctuations in vagal and sympathetic tone during the respiratory cycle, and also during slower periodic oscillations of arterial blood pressure, influence the variation in time between consecutive heartbeats.
198
SAIM - kap 2 - Hvad betyder heart rate variability (HRV) og hvad påvirkes det af?
HRV refers to the fluctuation (udsvinget) of beat-to-beat time intervals around their mean value.
HRV is influenced by baroreceptor function as well as by the respiratory cycle and sympathetic/parasympathetic balance.
The degree of HRV decreases with severe myocardial dysfunction and heart failure, as well as other causes of increased sympathetic tone.
199
SAIM - kap 2 - Hvad bruges signal-averages EKG (SAECG) til ?
Digital signal averaging of the E C G provides a means of
enhancing ECG signal resolution by discarding random
components (noise) so that small-voltage potentials that
may occur at the end of the QRS complex and into the early ST segment can be detected. These so-called ventricular late potentials can be found in patients with injured myocardium; they indicate the presence of conditions that predispose to reentrant ventricular tachyarrhythmias.
The presence of late potentials on SAECG has been identified in some Doberman Pinschers with ventricular tachycardia and significant ventricular dysfunction.
200
SAIM - Hvad bruges Echocardiography (hjerteultralydgrafi)
Echocardiography (cardiac ultrasonography) is an important noninvasive tool for imaging the heart and surrounding structures. Anatomic relationships as well as cardiac function can be assessed by evaluating cardiac chamber size, wall thickness, wall motion, valve configuration and motion, and proximal great vessels and other parameters. Pericardial and pleural fluid are easily detected, and mass lesions within and adjacent to the heart can be identified. Echocardiographic examination can usually be performed with minimal or no chemical restraint.
Sound waves do not travel well though bone (e.g., ribs) and air (lungs); these structures may preclude good visualization of the entire heart.
Three echo modalities are used clinically: M-mode, two-dimensional (2-D, realtime), and Doppler.
Higher frequency ultrasound permits better resolution of
small structures because of the beam characteristics of longer near field and lesser far field divergence. However, higher frequencies have less penetrating ability as more energy is absorbed and scattered by the soft tissues. Conversely, a transducer that produces lower frequencies provides greater penetration depth but less well-defined images.
Strongly reflective tissues are referred to as being hyperechoic or of increased echogenicity. Poorly reflecting tissues are hypoechoic; fluid, which does not reflect sound, is anechoic or sonolucent.
Optimal visualization generally is achieved for 2-D and M-mode studies when the ultrasound beam is perpendicular to the cardiac structures and endocardial surfaces of interest.
If the suspected lesion can be visualized in more than one
imaging plane, it is more likely to be real.
Light sedation is helpful if the animal does not lie quietly.
Buprenorphine (0.0075 to 0.01 mg/kg IV) with aceproma¬
zine (0.03 mg/kg IV) usually works well for dogs. Butorphanol (0.2 mg/kg IM) with acepromazine (0.1 mg/kg IM) is adequate for many cats, although some require more intense sedation. Acepromazine (0.1 mg/kg IM) followed in 15 minutes by ketamine (2 mg/kg IV) can be used in cats, but this regimen can increase heart rate undesirably.
201
202
SAIM - kap 2 - Hvad bruges to-dimensionel (2-D) Echocardiografi til?
A plane of tissue (both depth and width) is displayed using
2-D echocardiography. The anatomic changes resulting from various diseases or congenital defects are evident, although actual blood flow is not usually visualized with 2-D or M - mode imaging alone.
Most standard views are obtained from either the right or left parasternal positions (directly over the heart and close to the sternum). Images are occasionally obtained from subxiphoid (subcostal) or thoracic inlet (suprasternal) positions.
Images are described by the location of the transducer
and the imaging plane used (e.g., right parasternal
short-axis view, left cranial parasternal long-axis view).
The imaging allows an overall assessment of cardiac chamber orientation, size and wall thickness.
203
SAIM - kap 2 - Hvor tyk er højre ventrikels hjertevæg ifht. venstre ventrikels frie hjertevæg?
The RV wall is usually about one third of the thickness of the LV free wall and should be no greater than half its thickness.
204
SAIM - kap 2 - Hvad bruger man M-mode til ved echocardiografi og hvad er det?
This modality provides a one-dimensional view (depth) into
the heart.
M-mode images represent echos from various
tissue interfaces along the axis of the beam (displayed vertically on the screen). These echos, which move during the cardiac cycle, are displayed against time (on the horizontal axis).
Accurate placement of the M-mode beam using a
moveable cursor line superimposed on an appropriate 2-D
(real-time) image is important. M-mode images usually provide cleaner resolution of cardiac borders than 2-D because of higher sampling rate.
Standard M-mode views are obtained from the right parasternal transducer position. The M-mode cursor is positioned with 2-D guidance using the right parasternal
short-axis view.
Precise positioning of the ultrasound beam within the heart (perpendicular to the structures to be measured)
and clear endocardial images are essential for accurate
M-mode measurements and calculations.
The leading edge technique is used when possible (i.e., from the edge closest to the transducer [leading edge] of one side of the dimension to the leading edge of the other). In this way, only one endocardial surface is included in the measurement.
End diastolic and systolic LV internal dimensions and
wall thickness are usually obtained using M-mode, but appropriately timed 2-D frames can also be used.
Mitral valve motion is also evaluated with M-mode.
The diameter of the aortic root and sometimes its motion
are measured with M-mode.
Og andet.
205
SAIM - kap 2 - Hvornår måles diastoliske målinger ved Echocardiografi?
Diastolic measurements are made at the onset of the QRS
complex of a simultaneously recorded ECG.
206
SAIM - kap 2 - Hvornår måles systoliske målinger af LV ved Echocardiografi?
Systolic measurements of the LV are made from the point of peak downward motion of the septum to the leading edge of the LV free-wall endocardium at the same instant.
207
SAIM - kap 2 - Hvad bruges fractional shortening til ? Echocardiografi.
The fractional shortening (FS; % delta D) is commonly
used to estimate LV function. FS is the percent change in LV dimension from diastole to systole ([LVIDd - LVIDs]/LVIDd x 100).
It is important to note that this index, like others taken during cardiac ejection, has the significant limitation
of being dependent on ventricular loading conditions.
208
SAIM - kap 2 - Hvad giver reduceret LV afterload? Og hvad har det af betydning for fractional shortening? Echocardiografi.
For example, reduced LV afterload (as occurs from
mitral insufficiency, ventricular septal defect, or peripheral
vasodilation) facilitates ejection of blood and permits greater FS, although intrinsic myocardial contractility is notincreased.
209
SAIM - kap 2 - Hvad bruger man calculated end-systolic volume index (ESVI) til? Echocardiografi
The use of the calculated end-systolic volume index
(ESVI) has been suggested as a more accurate way to assess myocardial contractility i n the presence of mitral regurgitation.
210
211
SAIM - kap 2 - Hvis du skal måle LA størrelsen, hvilken form for echocardiografi vil du bruge?
LA size assessment is best done from 2-D images.
212
SAIM - kap 2 - Hvad bruges Doppler echocardiografi til?
Blood flow direction and velocity are imaged with Doppler
echocardiography. Several types of Doppler echocardiography are used clinically: pulsed-wave (PW), continuous-wave (CW), and color flow (CF) mapping.
Important clinical applications relate to identifying abnormal flow direction or turbulence and increased flow velocity. This allows detection and quantification of valvular insufficiency, obstructive lesions, and cardiac shunts.
The Doppler modality is based on detecting frequency
shifts between the emitted ultrasound energy and echoes
reflected from moving blood cells (the Doppler shift\*).
Echoes returning from cells moving away from the transducer are of lower frequency, and those from cells moving toward the transducer are of higher frequency.
213
SAIM - kap 2 - Hvordan måler man optimal blood flow profiles and calculation of maximal blood flow velocity (hastighed)?
Optimal blood flow profiles and calculation of maximal
blood flow velocity are possible when the ultrasound beam (Doppler echocardiografi) is aligned parallel to the flow. This is in contrast to the perpendicular beam orientation needed for optimal M-mode and 2-D imaging.
As long as the angle between the ultrasound beam and path of blood flow is less than 20 degrees, maximal flow velocity can be estimated with reasonable accuracy.
214
SAIM - kap 2 - Hvad er fordelen og ulempen ved pulsed wave (PW) Doppler echocardiografi?
The advantage of PW Doppler is that blood flow velocity, direction, and spectral characteristics can be calculated from a specific location in the heart or blood vessel. The main disadvantage is that the maximum measurable velocity is limited.
215
SAIM - kap 2 - Hvad skaber ventrikulær outflow obstruktioner?
Ventricular outflow obstruction causes more rapid flow acceleration, increased peak velocity, and turbulence.
216
SAIM - kap 2 - Hvordan placerer man pulsed wave Doppler echocardiografi bedst for at måle blodflowet forskellige ostier?
The four-chamber left apical view usually provides
optimal alignment for assessing **mitral inflow velocities;**
the left cranial short axis view is usually best for
**tricuspid inflow.** Peak systolic **pulmonary velocity** is ≤1.4 to 1.5 m/sec in most normal dogs. The left cranial views usually provide better flow alignment. **Maximal aortic/LV outflow velocitie**s are obtained in most dogs from the subcostal (subxiphoid) position; however, in some dogs the left apical view provides higher velocity recordings.
217
SAIM - kap 2 - Hvad er fordelen og ulempen ved Continuous wave Doppler echocardiografi?
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Continuous wave (CW) Doppler employs continuous and
simultaneous ultrasound transmission and reception along
the line of interrogation. Theoretically, there is no maximum velocity limit with CW Doppler, so high-velocity flows can be measured (Fig. 2-33). The disadvantage of CW Doppler is that sampling of blood flow velocity and direction occurs all along the ultrasound beam, not in a specified area (socalled range ambiguity).
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CW Doppler is employed if aliasing occurs with PW Doppler. (Pressure gradient estimation)
218
SAIM - kap 2 - Hvad bruger man Doppler estimation af tryk gradienter til?
Doppler estimation of pressure gradients is used in combination with M-mode and 2-D imaging to assess the severity of congenital or acquired flow obstructions.
Pressure gradient = 4(maximum velocity)2
219
SAIM - kap 2 - Hvad er color flow (CF) mapping?
Color flow (CF) mapping is a form of PW Doppler that
combines the M-mode or 2-D modality with blood flow
imaging. However, instead of one sample volume along
one scan line, many sample volumes are analyzed along
multiple scan lines. The mean frequency shifts obtained from multiple sample volumes are color-coded for direction (in relation to the transducer) and velocity. Most systems code blood flow toward the transducer as red and blood flow away from the transducer as blue. Zero velocity is indicated by black, meaning either no flow or flow that is perpendicular to the angle of incidence.
Differences in relative velocity of flow can be accentuated (fremhævet), and the presence of multiple velocities and directions of flow (turbulence) can be indicated by different display maps that use variations in brightness and color.
Signal aliasing is displayed as a reversal of color (e.g., red shifting to blue; Fig. 2-34). Turbulence produces multiple velocities and directions of flow in an area, resulting in a mixing of color; this display can be enhanced using a variance map, which adds shades of yellow or green to the red/blue display
220
SAIM - kap 2 - Hvad bruges Doppler tissue imaging til?
Doppler tissue imaging (DTI) is a modality used to assess
the motion of tissue, rather than blood cells, by altering the
signal processing and filtering of returning echoes.
221
SAIM - kap 2 - Hvordan fungerer transesophageal echocardiografi (TEE)?
Transesophageal echocardiography (TEE) uses specialized transducers mounted on a flexible, steerable endoscope tip to image cardiac structures through the esophageal wall. TEE can provide clearer images of some cardiac structures (especially those at or above the AV junction) compared with transthoracic echocardiography because chest wall and lung interference is avoided. This technique can be particularly useful for defining some congenital cardiac defects and identifying thrombi, tumors, or endocarditis lesions, as well as guiding cardiac interventional procedures (Fig. 2-37).
222
SAIM - kap 2 - Hvad påvirker central venetryk og hvad bruges det til?
Central venous pressure (CVP) is influenced by intravascular volume, venous compliance, and cardiac function. CVP measurement helps in differentiating high right heart filling pressure (as from right heart failure or pericardial disease) from other causes of pleural or peritoneal effusion.
But it is important to note that pleural effusion itself can increase intrapleural pressure enough to impair cardiac filling; this can raise CVP even in the absence of cardiac disease. Therefore CVP should be measured after thoracocentesis in patients with moderate- to large-volume pleural effusion.
CVP is sometimes used to monitor critical patients receiving large intravenous fluid infusions. However, CVP is not an accurate reflection of left heart filling pressure and thus is not a reliable way to monitor for cardiogenic pulmonary edema.
223
SAIM - kap 2 - Hvilke biomarkører bruger man til at opdage myocardie skade?
Cardiac troponins are more sensitive for detecting myocardial injury than cardiac-specific creatine kinase (CK-MB) and other biochemical markers of muscle damage.
Circulating concentrations of cardiac troponin I (cTnl) and cardiac troponin T (cTnT) provide a specific indicator of myocardial injury or necrosis.
After acute myocyte damage, serum cTn concentration increases within a few hours, peaks in 12 to 24 hours, and then declines over the next few weeks. Myocardial inflammation, trauma, congestive heart failure, hypertrophic cardiomyopathy, and gastric dilatation/volvulus have been associated with increased cardiac toponin concentrations. In dogs with congestive heart failure or hypertrophic cardiomyopathy, this probably relates to **continued myocardial remodeling**, not just acute damage from myocardial infarction.
224
SAIM - kap 2 - Hvilke biomarkører bruger man til at vurdere hjertesvigt?
The natriuretic peptides, ANP, BNP, and their precursors,
are other potentially useful biomarkers for assessing the
presence and possibly prognosis of heart failure. Circulating natriuretic peptide concentrations increase in association with vascular volume expansion and decreased renal clearance and when their production is stimulated (e.g., with ventricular strain and hypertrophy, hypoxia, or tachycardia).
BNP as well as NT-proANP are high in most cats with hypertrophic cardiomyopathy.
225
SAIM - kap 2 - Hvad bruger man et hjertekateter til?
Cardiac catheterization allows measurement of pressure,
cardiac output, and blood oxygen concentration from specific intracardiac locations.
