MD Cardiovascular System Pathophysiology 3

Question 1

A 55-year-old man undergoes cardiac catheterization after a large anterior STEMI. Which coronary artery territory is most likely occluded?

Accepted Answer

Left anterior descending artery (LAD)

Answer

The LAD supplies the anterior wall, apex, and anterior interventricular septum, making it the vessel most responsible for anterior ST-elevation myocardial infarction.

Question 2

Which compensatory mechanism in heart failure leads to cardiac remodeling and ultimately worsens long-term prognosis?

Accepted Answer

Chronic neurohormonal activation via RAAS and sympathetic nervous system

Answer

Chronic RAAS and sympathetic activation causes maladaptive cardiac remodeling—fibrosis, hypertrophy, and chamber dilation—that progressively worsens heart failure.

Question 3

Electrical alternans on ECG in a patient with hypotension and elevated JVP most likely indicates which condition?

Accepted Answer

Cardiac tamponade

Answer

Electrical alternans—beat-to-beat variation in QRS amplitude—results from the heart swinging within a large pericardial effusion, characteristic of cardiac tamponade.

Question 4

A patient with long-standing hypertension develops diastolic heart failure. The primary pathophysiologic abnormality is:

Accepted Answer

Impaired ventricular relaxation and increased chamber stiffness

Answer

Hypertensive heart disease causes concentric LV hypertrophy with increased collagen deposition, impairing active relaxation (lusitropy) and passive compliance.

Question 5

In a patient with pulmonary embolism, the right ventricle fails acutely despite normal baseline function. What is the critical mechanism?

Accepted Answer

Sudden increase in RV afterload exceeding its adaptive capacity

Answer

The thin-walled RV, unlike the LV, cannot acutely adapt to sudden pressure overload from massive PE, leading to acute RV failure and obstructive shock.

MD - Doctor of Medicine Practice Test

MD - Doctor of Medicine Practice Test

MD Cardiovascular System Pathophysiology 3