MD - Doctor of Medicine Cardiovascular System Pathophysiology Questions and Answers

Question 1

A 65-year-old male with a history of hypertension and hyperlipidemia presents for a routine check-up. He is asymptomatic. In the context of atherosclerotic cardiovascular disease, which of the following is considered the primary initiating event in the formation of an atheromatous plaque?

Accepted Answer

Endothelial dysfunction and increased permeability

Answer

The initial step in atherosclerosis is endothelial dysfunction, caused by risk factors like hypertension and hyperlipidemia. This dysfunction leads to increased permeability of the endothelial layer, allowing low-density lipoproteins (LDL) to enter the intima, where they become oxidized. This triggers an inflammatory response, monocyte recruitment, and the subsequent cascade of events leading to plaque formation.

Question 2

A 72-year-old female with chronic systolic heart failure has persistently elevated activity of the Renin-Angiotensin-Aldosterone System (RAAS). Which of the following is a direct pathophysiological consequence of increased Angiotensin II levels in this patient?

Accepted Answer

Potent vasoconstriction and stimulation of aldosterone release

Answer

Angiotensin II is a powerful vasoconstrictor that increases systemic vascular resistance (afterload). It also directly stimulates the adrenal cortex to release aldosterone, which promotes sodium and water retention, further increasing blood volume and cardiac workload. These actions are maladaptive in chronic heart failure, contributing to progressive cardiac remodeling and worsening of the condition.

Question 3

A 58-year-old male presents to the emergency department with severe, crushing substernal chest pain. An ECG is performed. Which of the following ECG findings is most indicative of an acute ST-segment elevation myocardial infarction (STEMI) resulting from a transmural ischemic injury?

Accepted Answer

New ST-segment elevation at the J-point in two or more contiguous leads

Answer

The hallmark of an acute STEMI is ST-segment elevation on an ECG, which signifies a full-thickness (transmural) injury to the myocardium due to complete coronary artery occlusion. The criteria generally require new ST elevation at the J point in at least two contiguous leads. While other changes like Q waves or T-wave inversions can be present, the acute elevation is the defining feature for this diagnosis.

Question 4

An 80-year-old patient is diagnosed with severe, calcific aortic stenosis. From a pathophysiological standpoint, what is the primary hemodynamic burden placed on the left ventricle as a result of this condition?

Accepted Answer

Pressure overload

Answer

Aortic stenosis is the narrowing of the aortic valve, which obstructs blood flow from the left ventricle into the aorta during systole. To overcome this obstruction, the left ventricle must generate a much higher pressure to eject blood. This sustained increase in resistance to ejection creates a chronic pressure overload on the ventricle, leading to compensatory concentric hypertrophy.

Question 5

A 45-year-old patient in the ICU develops septic shock secondary to pneumonia. Which of the following best describes the primary cardiovascular pathophysiology of this condition?

Accepted Answer

Distributive shock from profound systemic vasodilation

Answer

Septic shock is a classic example of distributive shock. The systemic inflammatory response to infection leads to the release of inflammatory mediators (like nitric oxide) that cause profound vasodilation and increased capillary permeability. This results in a maldistribution of blood flow, a decrease in systemic vascular resistance, and relative hypovolemia, leading to tissue hypoperfusion despite a potentially normal or high cardiac output initially.

MD - Doctor of Medicine Practice Test

MD - Doctor of Medicine Practice Test

MD - Doctor of Medicine Cardiovascular System Pathophysiology Questions and Answers