Cardiac Vascular Nursing Exam Cardiac Vascular Nursing Exam Pathophysiology & Disease Processes 1 — Questions and Answers
Question 1: Which pathophysiological mechanism is primarily responsible for ST-segment elevation in myocardial infarction (STEMI)?
- Complete occlusion of a coronary artery causing transmural ischemia (Correct answer)
- Partial occlusion causing subendocardial ischemia
- Coronary artery vasospasm without thrombosis
- Increased myocardial oxygen demand only
Correct 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.
Question 2: In heart failure with reduced ejection fraction (HFrEF), which neurohormonal compensatory mechanism initially maintains cardiac output but ultimately worsens outcomes?
- Activation of the renin-angiotensin-aldosterone system (RAAS) (Correct answer)
- Increased release of atrial natriuretic peptide (ANP)
- Decreased sympathetic nervous system activity
- Decreased antidiuretic hormone (ADH) release
Correct 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.
Question 3: Aortic stenosis causes pressure overload on the left ventricle, leading to which adaptive structural change?
- Concentric left ventricular hypertrophy (Correct answer)
- Eccentric left ventricular hypertrophy
- Left ventricular dilation without hypertrophy
- Right ventricular hypertrophy
Correct 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.
Question 4: Which cellular mechanism underlies the pathophysiology of atherosclerotic plaque formation in coronary arteries?
- Endothelial dysfunction allowing LDL infiltration and macrophage foam cell formation (Correct answer)
- Smooth muscle cell death leading to vessel wall weakening
- Excessive collagen degradation by matrix metalloproteinases
- Platelet aggregation without lipid involvement
Correct 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.
Question 5: A patient with mitral regurgitation will develop which hemodynamic consequence over time?
- Left atrial and left ventricular volume overload (Correct answer)
- Left ventricular pressure overload with normal atrial size
- Right ventricular hypertrophy as the primary change
- Decreased preload with normal ejection fraction
Correct 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.
Question 6: Cardiac tamponade impairs cardiac function primarily by which mechanism?
- External compression of the heart by pericardial fluid limiting ventricular filling (Correct answer)
- Direct myocardial toxicity from inflammatory mediators
- Increased afterload due to systemic vasoconstriction
- Reduced contractility from electrolyte imbalance
Correct 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.
Cardiac Vascular Nursing Exam Cardiac Vascular Nursing Exam Pathophysiology & Disease Processes 1
Which pathophysiological mechanism is primarily responsible for ST-segment elevation in myocardial infarction (STEMI)?