Cardiology

Question 1

What effect does cardiac tamponade have on the pulse quality?

Answer 1

Causes hypokinetic pulses due to decreased CO and pulsus paradoxus (weak or absent pulses with inspiration, stronger pulses with expiration)

Question 2

What is the law of Laplace?

Answer 2

Wall stress = pressure x radius/2 x wall thickness

Question 3

What effect can acromegaly have on an affected cat’s heart?

Answer 3

It can cause secondary hypertrophic cardiomyopathy (with or without LVOT obstruction)

Question 4

A canine patient has a CVP of 20 mmHg, ascites and a heart murmur. What is your diagnosis?

Answer 4

Right-sided heart failure

Question 5

How much does atrial fibrillation decrease the ventricular filling by?

Answer 5

20%

Question 6

What is the mechanism for a 3rd heart sound?

Answer 6

Early diastolic (ventricular) filling (more pronounced in failing/non-compliant ventricles, not audible in healthy dogs and cats)

Question 7

Which cardiac disease causes a splintered QRS complex on the ECG?

Answer 7

Tricuspid valve dysplasia

Question 8

What causes a split S2 sound and which diseases can it accompany?

Answer 8

Closing of the aortic and pulmonic valves at different times. Anything that changes the cycle length between LV and RV can cause a split S2 - e.g. pulmonary hypertension, BBB, PS, AS, ASD

Question 9

What effects does a patent ductus arteriosus cause on the heart (pressure vs volume overload, left vs right side)?

Answer 9

Left-sided volume overload

Question 10

Increase in ventricular filling increasing which cardiac protein in the blood (ANP, BNP, troponin 1, troponin C)?

Answer 10

BNP

Question 11

Which ions are responsible for each phase of the cardiac action potential in a non-pacemaker cell?

Answer 11

Phase 0 (depolarization): Sodium
Phase 1 (initial repolarization): Potassium 
Phase 2 (plateau): Calcium
Phase 3 (rapid repolarization): Potassium 
Phase 4 (resting membrane potential): Little net ion movement

Question 12

What is the effect of stimulation of carotid baroreceptors?

Answer 12

Elicits a vagal response, slows the heart rate

Question 13

Which ions are responsible for each phase of the cardiac action potential in a pacemaker cell?

Answer 13

Phase 0 (depolarization): Calcium
Phase 3 (repolarization): Potassium 
Phase 4 (resting membrane potential): funny channels (sodium and potassium), calcium

Question 14

How does calcium release from the SR in cardiac myocytes occur?

Answer 14

Cardiac SR Ca2+ release occurs mainly through CICR (calcium induced calcium release), and I(CaL) is the dominant Ca2+ source

Question 15

What is involved in excitation-contraction coupling and sending the action potential?

Answer 15

T tubules

Question 16

What causes increased pulse pressure/hyperdynamic pulses?

Answer 16

Aortic insufficiency

Question 17

What does atrial natriuretic peptides (ANP) do?

Answer 17

Decrease sodium and water reabsorption

Question 18

Differential for a dog with jugular pulses, no murmur, split S2?

Answer 18

Pulmonary hypertension

Question 19

What is the treatment for atropine responsive 2nd degree AV block?

Answer 19

Propantheline

Question 20

What is the most common cause of PHT in dogs?

Answer 20

Group II = MMVD

Question 21

In which canine breed has a nutritional form of taurine-associated DCM been identified?

Answer 21

Golden Retrievers

Question 22

What mutation in Maine Coons has been identified as a genetic cause of HCM?

Answer 22

MyBPC3-A31P