Cardiac Vascular Nursing Exam Pathophysiology & Disease Processes Flashcards

Which pathophysiological mechanism is primarily responsible for ST-segment elevation in myocardial infarction (STEMI)?

Answer: Complete occlusion of a coronary artery causing transmural ischemia

STEMI results from complete coronary artery occlusion, typically by a thrombus, causing full-thickness (transmural) myocardial ischemia that elevates the ST segment.

In heart failure with reduced ejection fraction (HFrEF), which neurohormonal compensatory mechanism initially maintains cardiac output but ultimately worsens outcomes?

Answer: Activation of the renin-angiotensin-aldosterone system (RAAS)

RAAS activation causes sodium and water retention and vasoconstriction, which initially supports blood pressure but chronically increases cardiac workload and promotes remodeling.

Aortic stenosis causes pressure overload on the left ventricle, leading to which adaptive structural change?

Answer: Concentric left ventricular hypertrophy

Pressure overload from aortic stenosis causes concentric hypertrophy, where sarcomeres replicate in parallel, thickening the ventricular wall without chamber dilation.

Which cellular mechanism underlies the pathophysiology of atherosclerotic plaque formation in coronary arteries?

Answer: Endothelial dysfunction allowing LDL infiltration and macrophage foam cell formation

Atherosclerosis begins with endothelial injury, allowing LDL to enter the intima where oxidized LDL is engulfed by macrophages forming foam cells, initiating the plaque.

A patient with mitral regurgitation will develop which hemodynamic consequence over time?

Answer: Left atrial and left ventricular volume overload

Mitral regurgitation causes blood to flow backward into the left atrium during systole, creating volume overload in both the left atrium and, compensatorily, the left ventricle.

Cardiac tamponade impairs cardiac function primarily by which mechanism?

Answer: External compression of the heart by pericardial fluid limiting ventricular filling

Pericardial fluid accumulation raises intrapericardial pressure, compressing all cardiac chambers and severely restricting diastolic filling, reducing stroke volume.