Exam 4 Flashcards
Heart Sounds
o S1 – mitral & tricuspid – longer lower pitch
o S2 – aortic & pulmonic – higher shorter pitch
o Gallop – S3 & 4 – abnormal in SA
Describe Murmurs
o Point of max intensity (loudest or easiest to feel)
o Systolic, diastolic, continuous
o Radiation
o Pitch: harsh vs musical
o Grade
Grading Murmurs
o 1/6 – intermittent in one valve area
o 2/6 - consistent in one valve area
o 3/6 – multiple vLVE AREAS
o 4/6 – multiple valve ares & louder than 3
o 5/6 – palpable thrill
o 6/6 – can hear w/o stethoscope
Puppy Murmur
o Normal puppies can have 1-2/6
o 1-2/6 should go away
o If becomes 3/6 or greater -> send for echo
Causes For Physiologic Murmurs
o Anemia
o Hyperthyroidism
o Fever
o Breed (boxers)
Gallop Vs Click
Ventricular gallop
* S3 Diastole
* Due to high atrial P + poorly compliant ventricle
* Normal in horses & cattle
Atrial gallop
* S4 Diastole
* Due to increased atrial contraction P
Clicks
* Systole
* Due to mitral and tricuspid prolapse
Pulsus Paradoxus
o Pericardial dz w/ tamponde
o Decrease in strength of pulse during inspiration
Bounding Pulses
o Exercise, excitement, stress
o Early shock
o Aortic insufficiency
o L to R patent ductus arterisosus
o Hyperthyroidism
Weak Arterial Pulse
o Poor perfusion
o Shock
o Heart failure
o Aortic stenosis
Affects of Heart Failure on Heart Rate
o HR is Constant battle between sympathetic and parasympathetic tone
o Heart failure increases sympathetic tone
->
o Increased vagal tone
Systolic Vs Diastolic Failure
Systolic
* Impaired contractility
* Valve leakage caused by degeneration (endocardiosis), valve infection (endocarditis), or congenital malformations
* Dilated cardiomyopathy (primary or genetic)
* Myocardial damage
* Volume recirculation caused by congenital defects (patent ductus arteriosus and ventricular septal defects)
* Primary tachyarrhythmias (supraventricular or ventricular)
Diastolic
* Impaired relaxation
* Chronic afterload elevation (systemic or pulmonary hypertension)
* Hypertrophic cardiomyopathy (primary or genetic)
* Pericardial disease (fluid accumulation or
constriction)
* pulmonic and aortic valve stenosis
(semilunar)
Signs of Congestive Heart Failure in Dogs
- General weight gain
- SQ edema - rare
L sided
* Pulmonary edema
R sided
* Ascites
* Pleural effusion
* Pericardial effusion
Signs of Low Output Failure
- Hypotension
- Hypothermia
- Bradycardia
- Cold extremities
- Pale mucous membranes
Consequences of Decreased Stroke Volume
Remodeling
* eccentric hypertrophy (dilation) or concentric hypertrophy (thickening)
Elevated catecholamines
* increased HR, O2 consumption, & decreased time in diastole
Renal effects
* decreased perfusion -> upregulate RAAS -> increased afterload, renal fibrosis, fluid retention
3 Results & Causes of Heart Remodeling
Eccentric (dilation)
* Valve regurgitation
* DCM
* Volume recirculation due to congenital defects
* Myocardial damage
Concentric (thickening)
* Valve narrowing
* Chronic increased afterload
* HCM
Cell death & fibrosis
Mechanisms Behind Arrhythmias
Increased Automaticity
* Higher rate of firing of nodes
Re-entry
* Abnormal tissue allows conduction do go into circuit rather than through AV node
Abnormal Ca cycling
* Weird spike of Ca
* Early or delayed repolarizations
Frequency of Echo Probe
o High frequency – better resolution
o Low frequency – better penetration
Color Doppler
o BART Map
o Blue away
o Red toward
o Green turbulence
o Nyquist level high -> less turbulence shown
Continuous Vs Pulse Wave Doppler
Continuous Wave Doppler
o Sends continuous Doppler signal
o quantify maximum velocity along one line.
o needed for congenital lesions and to determine velocity of valve regurgitation
Pulse Wave Doppler
o assess or pulse a single area and determine velocity and time of waves in a defined area
o Only able to determine low velocity (usually <1.5 m/s)
o Used to assess diastolic function and others
Assessment of Systolic Vs Diastolic Function w/ Echocardiography
Systolic Function
o Fraction shortening %
o Ejection fraction %
Diatsolic Function
o Mitral inflow E & A waves
o Isovolumetric relaxation time
Measuring Chamber Dimensions on Echo
o L atrium to aorta ratio
o R atrium & ventricle subjectively compared to L
What should be on an echo report
o chamber size and if enlarged the severity
o Left ventricular systolic function & maybe diastolic
o valve anatomy and any regurgitation or stenosis.
Natriuretic Peptide; What is it, Use, Tests, Physiological Contraindications
o B-Type natriuretic peptide (BNP)
o Originally found in the pig brain
Use
* Atrial and ventricular (more ventricular) myocytes in response to increase volume or stretch
* Used to diagnose cardiomyopathies
Tests
* IDEXX has Snap for CATS
* send out test for dogs asymptomatic
* Bionate in house machine
Physiological Contrainidications
* Decreased by increased thyroid
* renal issues cause odd values
Marker for Myocyte Injury; What is it, Use, Why use, Physiological Contraindications
o Troponin = “ALT” of the heart
Use
* Myocardial injury from myocarditis, ischemia, cardiomyopathy
* Release into blood
Why to Use
* Unexplained arrhythmias -> myocarditis
* Abnormal appearing myocardium on echocardiogram -> myocarditis or neoplasia
Physiological Contrainidications
* Other dz can elevate Triponin
Why test Taurine Levels
o Taurine deficiency can lead to DCM
o Especially think of cockerspaniels
Why Test Carnitine Levels
o Decreased blood levels associated w/ DCM in boxers
o Can treat w/ L-carnitine
Genetic Testing for HCM
o Ragdolls and Maine Coons
o Phenotype does not equal genotype
o Helpful in breeding animals
o Current test are available at NC state and UC Davis.
o Blood or mucosal swab
Genetic Testing for Boxer ARVC & Doberman DCM
o Helpful in breeding animals.
o Current test are available at NC state
o Blood or mucosal swab.
o Striatin (Boxer)
o PDK 4 (Dobermans)
Things to Pay Attention to When Looking at Thoracic Rads
o Cardiac size and if chambers are enlarged
o Pulmonary vessels size
o Pulmonary pattern (interstitial, bronchial, alveolar)
o Great vessels and mediastinal structures
Views Needed for Thoracic Radiographs
o Need 2 views
o VD for lungs
o DV for cardiac structures
L Atrial & Ventricular Enlargement on Rads
Lateral
* “tall” heart – L ventricle enlargement
* Loss of caudal waist – L atrium enlargement
DV
* Widening of the left and right bronchus (bow legged cowboy) – L atrial enlargement
* “3 O clock” enlargement – L auricle (cats & heart dz)
* “4-6 O clock” enlargement – L ventricle
R Atrial & Ventricular Enlargement on Rads
DV
* “reverse D” on R side – RV enlargement or PA enlargement
* buldge at “9 O clock” – R atrial enlargement
Aortic Buldge
o Small buldge at “1-3 O clock”
Vertebral Heart Score & Pulmonary Vessel Size
o Draw line from carina to base of heart – length
o Draw Line horizontally - width
o # of vertebral bodies width + length = VHS (should be less than 10.5)
o Vessels should not be wider than 9th rib
Alveolar Vs Interstitial Vs Bronchial Pattern
Alveolar Pattern
o completely whited out
o Silhouette sign - can’t see border of heart
Interstitial Pattern
o More white than should be
o Still see cardiac silhouette
Bronchial Pattern
o Round structures all throughout lungs
Diagnosing L sided CHF in Dogs Vs Cats
Dogs
o L atrial enlargement +
o Pulmonary venous congestion +
o Pulmonary infiltrates consistent w/ CHF (perihilar region)
Cats
o Pulmonary edema (not always perihilar)
o Pleural effusion
o Or both
Waves on an ECG
P wave
* Atrial depolarization
QRS
* Depolarization of ventricles
T
* Ventricular recovery
Info on an ECG
o Heart rate
o Amplitude and duration changes of P wave
and QRS deflection
o T wave changes
o Mean Electrical Axis (MEA)
o Detection and classification of ectopic beats**
o Detection and classify the etiology of
brady/tachyarrhythmias
Telemetry ECG
o ECG info sent to central computer
o 24-48hrs of data
Used for monitoring
* post-surgery
* response to anti-arrhythmics
* metabolic or endocrine dz
Things to Remember when Recording ECG
o Best position is R lateral recumbancy
o Use highest voltage
Difficulty seeing P waves?
* Increase amplitude
* Turn off filter
Sinus bradycardia; Causes, Treatment
Due to
* GI dz
* Resp dz
* Ocular dz
* Neuro dz
Fix
* Atropine or glycopyrrolate if occurring under anesthesia
Sinus tachycardia; Ventricular or supra? Causes
o Supraventricular arrhythmia
Due to
* Pain
* Anemia
* Dehydration
1st Degree AV Block
o increased length between P and QRS
o normal or high vagal tone
o can be secondary to digoxin, diltiazem, beta blockers
2nd Degree AV Block
o more P waves than QRS
o high vagal tone
o treat w/ atropine
Atropine Response Test
o atropine SQ or IM
o wait 30 mins
Positive response =
o double original rate or >140 BPM
OR
o Blocked P waves go away
High Grade 2nd Degree AV Block
o MANY more P waves than QRS
o Try atropine
o Usually need pacemaker
3rd Degree AV Block
o more P waves than QRS
o Ps seem independent of QRS
o Try atropine
o need pacemaker urgently if syncope
o Junctional or ventricular escape rhythm
o Syncope can occur
Sick Sinus Syndrome
o Long pause w/ no beats
o And escape QRS beats
o Need pacemaker
o May be associated w/ tachycardia
o Sinus node problem w/ lack of escape beats
Atrial Standstill or Sinoventricular Rhythm
o No P waves
o Check K levels (often high)
o If K normal -> atrial cardiomyopathy
Atrial Standstill Hyperkalemia Treatment
Protect myocardium while fixing underlying cause
o Ca gluconate (protect myocardium)
Fix Hyperkalemia
o Dextrose
o Insulin
o Fluid for diuresis
Atrial Standstill Vs Sick Sinus Syndrome
Atrial Standstill
* Consistent lack of P
Sick Sinus
* Intermittent lack of P
Premature Ventricular Complexes; Treatment
o Treat depending on many factors
o Beat too soon near previous beat
Treatment
* SPAM
* Sotalol
* Procainamide
* Atenolol
* Amiodarone
* Mexiletine
When to Avoid Beta Blockers
o Decreased systolic function
o CHF
Ventricular Tachycardia; What does it look like, treatment
o P-QRS-T present but fast and irregularly placed
Treatment
* Lidocaine 2 mg/kg in dogs bolus -> then CRI
* Amidoarone
* Procainamide
* Esmolol
* Electrical cardioversion
Atrial or Supraventricular Complex; What does it look like, What does it mean, Control Rate, Suppress Ectopic Focus
o Looks normal but P-QRS-T comes to close to previous one
o Unlikely to treat single APCs
o treat high frequency
or complexity
o Look for structural heart disease
o Could be precursor to worsening arrhythmia ( A fib)
Control Rate
* DAD
* Digoxin
* Atenolol
* Diltiazem
Suppress Ectopic Focus
* Sotalol
* Procainamide
Atrial Fibrilation; What does it look like? Control Rate, Control Rythm
- No consistent P waves
- Irregular QRS-QRS intervals
- Often Tachycardia w/ structural heart dz
Control Rate
* DAD
* Digoxin
* Atenolol
* Diltiazem
Control Rhythm
* Quinidine (horses)
* Sotalol
* Amiodarone
* Electrical cardioversion
Atrial Flutter; What does it look like? Treatment
o Many P waves quickly in a row
o Type of supraventricular tachycardia
o Irregular or regular
Treatment
* DAD
* Digoxin
* Atenolol
* Diltiazem
Bundle Branch Block; What does it look like?
- L or R
- Look for structural dz
- Progression to complete block vs normal variant
- P & QRS waves present
- Happen one right after another w/ no space
Vetricular Fibrilation; What does it look like? Treatment.
o Crazy ECG
o Are leads attached?
o Need to defibrillate
Electrical Alterans; What does it look like? Why?
o QRS waves stair step in height
o Can be secondary to pericardial effusion
Idioventricular Rhythm; What does it look like? Cause, Treatment
o Normal P-QRS-T waves with occasional weird/wide QRS w/o P & T
o Rate 120-160
Cause
* GDV, splenic dz, septic conditions
Treatment
* Pain control
* Check K levels
ST Segment Depression or Elevation; What does it look like? Cause
o Large pause btwn QRS & T
o Myocardial ischemia
