Canine Flash Notes - Cardiology Review Flashcards
what are some examples of valvular diseases in dogs?
endocardiosis, congenital aortic stenosis, congenital pulmonic stenosis, congenital av valve dysplasia, bacterial endocarditis, av valvular regurgitation due to cardiomegaly
what is S1?
heart sound one, lub - closure of the AV valves (start of ventricular systole)
what is S2?
second heart sound, dub - closure of semilunar valves (aortic & pulmonic valves) start of ventricular diastole
what is the most common cause of a split S2 sound?
heartworm disease - due to delayed closure of a semilunar (aortic or pulmonic) valve
T/F: S2 may be absent in arrhythmias if the ventricles do not fill adequately (semi lunar valves don’t open)
true
what is the difference between the stenosis & regurgitation?
stenosis - obstruction of flow, usually congenital
regurgitation (insufficiency) - incomplete closure of valve, either congenital or acquired
what is the purpose of the left & right av valves?
prevent back flow of blood into the atria during ventricular systole
what is the purpose of the pulmonic & aortic semi-lunar valves?
prevent back flow of blood into ventricles during ventricular diastole
what is the hallmark of valvular disease in dogs?
murmurs - due to turbulent blood flow over the valve
T/F: severity of disease & severity of murmur are not correlated but progression of a murmur does indicate a progression of disease
true
what are some examples of causes of low grade murmurs with no other signs of cardiac disease?
anemia, fever, anxiety, kittens/puppies under 6 months old, hypoproteinemia, & athletic heart
what are some murmurs that should be worked up with ECG, rads, & echo?
murmur with clinical signs of cardiac disease
continuous or diastolic murmur
gallop rhythm
pulse deficits
progression of murmur
murmur when anesthesia is contemplated due to increased risk (grades 2-6, check for cardiac disease)
what are the different grades of murmurs?
1 - very soft, minutes to hear in a quiet room
2 - soft murmur but definite
3 - moderate
4 - loud, no precordial thrill
5 - loud with palpable precordial thrill
6 - loud, precordial thrill & heard with the stethoscope off of the chest wall
what are examples of pathologic systolic murmurs? diastolic murmurs? continuous murmur?
overall - stenosis, regurgitation, & shunts
systolic - left av valve regurgitation, aortic stenosis, pulmonic stenosis, right av valve regurgitation, & VSD
diastolic - aortic valve regurgitation
continuous - PDA
T/F: atrial septal defects, pulmonic regurgitation, & tetralogy of fallot are rare causes of murmurs
true
what are radiographic findings seen with right atrial enlargement?
lateral view - elevation of trachea at carina, loss of cranial waist
DV view - 9 to 11 o’clock bukge
what are radiographic findings seen with left atrial enlargement?
lateral - elevated trachea & carina, separation of mainstem bronchi (left above right)
DV view - 2 to 3 o’clock bulge (auricle), cowboy legs (spread mainstem bronchi)
what are radiographic findings seen with right ventricular enlargement?
lateral - 6 to 9 o’clock bulge, more sternal contact, trachea & carina elevation, & apex elevated off of sternum
DV view - 6 to 9 o’clock bulge (backwards or reverse D) & apex shifted more to the left
what are radiographic findings seen with left ventricular enlargement?
lateral - loss of caudal waist, 3 to 6 o’clock bulge
DV view - rounding at 3 to 5 o’clock & apex shifted right
what are causes of an enlarged aortic arch seen on rads? what is seen?
PDA, aortic stenosis, & aortic aneurysm
lateral - elongated cardiac silhouette, protrusion of cranial heart border at 11 to 1 o’clock
DV view - widened aortic arch at 11 to 1 o’clock
what are causes of an enlarged MPA seen on rads? what is seen?
pulmonic stenosis, HWD, PDA, septal defects with left to right shunting (VSD, ASD)
what is the main cause of pulmonary edema in dogs?
usually caused by left sided congestive heart failure - fluids back up into the pulmonic circulation
what are the 2 types of pulmonary edema? how are they differentiated on rads?
interstitial edema - fluid in lung tissue, vessels are fuzzy but evident, more opaque lung field (linear or nodular, greater in perihilar area) & air still evident in lungs
alveolar edema - alveoli are filled with fluid, opaque lung field, no air in lungs, air bronchograms, & no vasculature seen
what are the radiographic findings of overcirculation? what are some of the main causes? what are the differentials you should consider?
arteries larger than veins & more opaque lungs
HWD, PDA, left to right shunts (VSD, ASD), CHF, & fluid overload
ddx - expiratory rad or underexposure
what are the radiographic findings of undercirculation? what are some of the main causes? what are the differentials you should consider?
more radiolucent lungs, arteries smaller than veins
causes - right to left shunt, pulmonic stenosis, hypovolemic shock, adrenal insufficiency
ddx - emphysema, over-inflation, & overexposure
what are the main differentials to consider for pleural effusions?
hydrothorax, ascites, right sided CHF, right av tricuspid regurgitation, pulmonic stenosis, HWD, pericardial effusion/pericarditis, tetralogy of fallot, uremia, hypoproteinemia, & fluid overload
other pleural effusions - pyothorax, hemothorax, chylothorax, neoplasia, & pleuritis
what are the main cardiac differentials to consider for pulmonary edema?
cardiogenic edema with visible cardiomegaly - left sided CHF, chronic MVD, cardiomyopathy, ruptured chordae tendinae
cardiogenic edema without cardiomegaly - electrical shock, trauma, cardiomyopathy in some cases, tachyarrhythmia, & myocardial depressants
what are some causes of non-cardiogenic pulmonary edema?
infection, toxin, allergy, drowning event, venous obstruction, hypoalbuminemia
what are some causes of increased tissue density often mistaken for pulmonary edema?
interstitial fibrosis, interstitial pneumonia, atelectasis, allergic conditions, & lungworms
what is seen on radiographs in a dog with pleural effusion?
lat - increased opacity in ventral thorax & scalloped appearance due to fluid in tissues
DV view - retraction of lungs from thoracic wall, blunting of costophrenic angles, widening of mediastinum, scalloped appearance, & blurring/disappearance of cardiac silhouette
if you see ascites & hepatomegaly in an animal on rads, what do you suspect?
right sided heart failure - fluid back up into the body (systemic veins)
what is m-mode for echos? what is it used for? what does it requires?
ice pick images of the heart that gives lines for ventricles, left atria, aorta, valves
requires viewing movement of the heart over time
uses - measures cardiac wall thickness, chamber size, cardiac contractility (fractional shortening), & valves in motion
what is the purpose of using doppler on a cardiac ultrasound?
compares the frequency of transmitted ultrasound with received US of moving cells (blood cells), cells moving towards the transducer have a higher frequency than those moving away
used to estimate velocity of blood flow
what does a p-wave indicate on an ecg?
atrial depolarization
what does the p-r interval indicate on an ecg?
delay of impulse through AV node & bundle of his
what does the qrs complex indicate on an ecg?
ventricular depolarization
what does a q-wave indicate on an ecg?
depolarization of septum
what does a r-wave indicate on an ecg?
depolarization of left ventricle
what does a s-wave indicate on an ecg?
depolarization of right ventricle
what does a s-t segment indicate on an ecg?
interval of ventricular systole
what does a q-t segment indicate on an ecg?
ventricular depolarization & repolarization
what does a t-wave indicate on an ecg?
repolarization of ventricles
what are the goals in heart failure management?
- maintain or increase cardiac output
- minimize myocardial oxygen demand
- reduce activity & anxiety
- relieve fluid accumulation (edema)
- control rhythm disturbances
what are examples of bradycardic arrhythmias?
sinus bradycardia, atrial/sinoatrial standstill, sick sinus syndrome, 1st degree av block, 2nd degree av block, 3rd degree av block, junctional rhythm, & branch blocks
what are examples of tachycardic arrhythmias?
atrial tachycardia, atrial fibrillation, junctional tachycardia, ventricular tachycardia, ventricular fibrillation, & cardiac arrest
what treatment is used for heart disease & heart failure?
rest + O2 + diuretics + digoxin + anti-arrhythmics
what medication should not be given to animals with HCM? what do you give them instead?
digoxin - not a contractility problem
diltiazem - cause relaxation to increase ventricular filling
what are some surgical heart diseases?
PDA, PPDH, PS, & large septal defects
what are some ecg findings from animals with congenital cardiac defects?
atrial enlargement - big p wave
left ventricular enlargement - tall wave
right ventricular hypertrophy - right axis deviation
widened QRS
what are the most common congenital cardiac defects in dogs & cats?
dogs - PDA
cats - av valvular dysplasia
what rhythm is seen on this ecg strip?
sinus bradycardia, HR <70 for a dog & <90 for a cat
what rhythm is seen on this ecg strip?
sinoatrial block (arrest) - pause of 2 or more r-r intervals, clinically insignificant
what rhythm is seen on this ecg strip?
mobitz type I 2nd degree av block
p-r prolongs until a QRS is dropped
what rhythm is seen on this ecg strip?
dropped QRSs (bigeminy or trigeminy) but p-r intervals are constant
what rhythm is seen on this ecg strip?
atrial standstill (hyperkalemia) - no p waves
what rhythm is seen on this ecg strip?
1st degree av block, long p-r interval, delayed conduction impulse through av node to ventricle, dogs > 0.14 sec & cats > 0.05 sec
what rhythm is seen on this ecg strip?
sinus tachycardia - normal ecg just fast rate
what rhythm is seen on this ecg strip?
atrial APCs - premature P-QRS-T with a pause
what rhythm is seen on this ecg strip?
paroxysmal atrial tachycardia - fast HR & 3 or more APCs
what rhythm is seen on this ecg strip?
atrial flutter - no p waves, coarse f waves
what rhythm is seen on this ecg strip?
atrial fibrillation - fine f waves, rapid, irregularly regular ventricular rate
what rhythm is seen on this ecg strip?
junctional (av node - his purkinje) premature contractions - negative p waves, digitalis toxicity
what rhythm is seen on this ecg strip?
junctional rhythm - fast or slow JPCs, negative p waves, spontaneously reverts to bradycardia or tachycardia
what rhythm is seen on this ecg strip?
ventricular premature contractions - QRS is wide & bizarre
what rhythm is seen on this ecg strip?
ventricular tachycardia - 4 or more VPCs in a row
what rhythm is seen on this ecg strip?
ventricular fibrillation - continuous chaotic bizarre positive & negative oscillations, medical emergency, needs CPR
what conduction disorder is shown on this wave form?
intraventricular conduction blocks - QRS is prolonged, microscopic intraventricular myocardial infarct
what conduction disorder is shown on this wave form?
pre-excitation syndromes - QRS widened with notched r’s delta waves, re-entrant impulses
what conduction disorder is shown on this wave form?
sick sinus syndrome - bradycardia pattern seen often in female mini schnauzers, weakness & syncope
what are your differentials for slow, regular rhythms?
sinus bradycardia, complete AV block (ventricular escape rhythm), & atrial standstill (ventricular escape rhythm)
what are your differentials for slow, irregular rhythms?
sinus block/arrest, sick sinus syndrome, & 2nd degree av block
what are your differentials for fast, regular rhythms?
sustained ventricular tachycardia, atrial tachycardia, & sinus tachycardia
what are your differentials for fast, irregular rhythms?
APCs, paroxysmal atrial tachycardia, atrial flutter/fibrillation, VPCs, & paroxysmal ventricular tachycardia
what are the 4 main groups of drugs used to treat arrhythmias?
- sodium channel blockers - decreases conduction, use on ventricular arrhythmias
- beta blockers - decrease sympathetic tone, for supraventricular & ventricular arrhythmias
- potassium channel blockers - supraventricular tachycardia
- calcium channel blockers - atrial fibrillation, cardiac disease, & bradycardia
what rhythm seen on ecg precedes cardiac arrest?
ventricular fibrillation
