MD Cardiovascular System Pathophysiology 4

Question 1

Pulsus paradoxus (>10 mmHg fall in SBP with inspiration) is caused by which mechanism in cardiac tamponade?

Accepted Answer

Exaggerated interventricular dependence as RV filling compromises LV filling

Answer

Inspiration increases RV filling, but the tamponade-restricted pericardial space forces the interventricular septum to bow into the LV, reducing LV stroke volume and systolic pressure.

Question 2

A 48-year-old woman with systemic lupus erythematosus develops pleuritic chest pain and friction rub. Libman-Sacks endocarditis in SLE most commonly affects which valve?

Accepted Answer

Mitral valve (mitral regurgitation)

Answer

Libman-Sacks endocarditis produces sterile verrucous vegetations on both surfaces of the mitral valve, causing mitral regurgitation.

Question 3

Which mechanism explains the wide pulse pressure seen in aortic regurgitation?

Accepted Answer

Elevated systolic pressure from increased stroke volume and low diastolic pressure from regurgitant runoff

Answer

In AR, the large forward stroke volume raises systolic pressure, while diastolic runoff back into the LV lowers diastolic pressure, widening the pulse pressure.

Question 4

A patient with inferior MI develops complete heart block. The culprit artery and mechanism are most likely:

Accepted Answer

RCA occlusion causing ischemia of the AV node supplied by posterior AV nodal artery

Answer

The AV node is supplied by the AV nodal artery, a branch of the RCA in ~90% of patients; inferior MI from RCA occlusion frequently causes AV nodal block.

Question 5

In a patient with severe mitral regurgitation, pulmonary capillary wedge pressure tracing will show:

Accepted Answer

Large 'v' wave from systolic regurgitant flow into the left atrium

Answer

During systole, regurgitant flow from the LV into the LA generates a large 'v' wave on the PCWP tracing, proportional to the severity of regurgitation.

MD - Doctor of Medicine Practice Test

MD - Doctor of Medicine Practice Test

MD Cardiovascular System Pathophysiology 4