Cardiology Quiz: Part 3
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1. According to the New York Heart Association (NYHA) functional classification, a patient with marked limitation of physical activity who is comfortable only at rest is classified as:
Explanation: NYHA Class III indicates marked limitation of physical activity. Less than ordinary activity causes fatigue, palpitation, or dyspnea, but the patient is comfortable at rest. Class IV patients have symptoms at rest.
2. Which physiological maneuver typically INCREASES the intensity of the murmur in Hypertrophic Obstructive Cardiomyopathy (HOCM)?
Explanation: The Valsalva maneuver (strain phase) decreases venous return (preload) to the heart. In HOCM, a smaller left ventricular volume worsens the outflow tract obstruction, making the murmur louder.
3. Rheumatic heart disease most commonly leads to stenosis of which cardiac valve?
Explanation: The mitral valve is overwhelmingly the most frequently involved valve in rheumatic heart disease, almost always presenting later in life as mitral stenosis.
4. A visual disturbance described as seeing “yellow-green halos” around objects is a classic side effect of toxicity from which medication?
Explanation: Xanthopsia (seeing yellow-green halos) is a classic neurological manifestation of digoxin toxicity, alongside nausea, vomiting, and characteristic arrhythmias.
5. What is the definitive treatment of choice for a Stanford Type A aortic dissection?
Explanation: Stanford Type A dissections involve the ascending aorta and carry a very high risk of rupture or tamponade, requiring emergent open surgical repair. Type B dissections (descending only) can often be managed medically.
6. A normal resting Ankle-Brachial Index (ABI) used to screen for peripheral artery disease typically falls within which range?
Explanation: A normal ABI is between 0.91 and 1.30. Values below 0.90 indicate peripheral arterial disease (PAD), while values above 1.30 suggest non-compressible, calcified vessels.
7. Amiodarone belongs primarily to which class of antiarrhythmic drugs according to the Vaughan Williams classification?
Explanation: While Amiodarone has characteristics of all four classes, it is primarily categorized as a Class III agent, prolonging phase 3 of the cardiac action potential by blocking potassium channels.
8. What is the most common viral etiology of acute myocarditis in North America?
Explanation: Coxsackievirus B (an enterovirus) has historically been recognized as the most common viral cause of acute myocarditis, though parvovirus B19 and HHV-6 are also highly prevalent in recent molecular studies.
9. Which of the following is considered a MAJOR criterion in the modified Jones Criteria for diagnosing Acute Rheumatic Fever?
Explanation: The major criteria (JNES) include Joint involvement (polyarthritis), (Myocarditis/Carditis), Nodules (subcutaneous), Erythema marginatum, and Sydenham chorea. The others listed are minor criteria.
10. Which class of medications is the first-line treatment for preventing coronary vasospasm in Prinzmetal (variant) angina?
Explanation: Calcium channel blockers (like diltiazem or amlodipine) promote vasodilation and prevent coronary artery spasm. Beta-blockers (especially non-selective ones) are generally avoided as they can exacerbate vasospasm by leaving alpha-receptors unopposed.
11. Dressler syndrome is best described as:
Explanation: Dressler syndrome is a delayed, immune-mediated pericarditis that develops 2 to 10 weeks after a myocardial infarction, differentiating it from early peri-infarction pericarditis.
12. A harsh, holosystolic murmur heard best at the left lower sternal border is most indicative of which congenital defect?
Explanation: This is the classic description of a VSD murmur. The smaller the defect, the louder and harsher the murmur tends to be due to high turbulence.
13. Second-degree AV block, Mobitz Type I (Wenckebach) is characterized on an ECG by:
Explanation: Wenckebach phenomenon exhibits progressive AV node fatigue, seen as a lengthening PR interval on successive beats until the node fails to conduct, resulting in a dropped QRS.
14. What is the most common cyanotic congenital heart disease diagnosed IN THE NEONATAL PERIOD (at birth)?
Explanation: While Tetralogy of Fallot is the most common cyanotic defect overall, TGA is the most common cyanotic lesion presenting in the immediate neonatal period (within the first week of life).
15. What is the most severe, life-threatening cardiovascular complication associated with Marfan syndrome?
Explanation: Patients with Marfan syndrome have cystic medial necrosis of the aorta, making aortic root dilation leading to aneurysms and catastrophic dissection the primary cause of premature death.
16. The classic symptomatic triad of severe aortic stenosis includes dyspnea, angina, and:
Explanation: The classic presentation of severe symptomatic AS is captured by the acronym SAD: Syncope (especially exertional), Angina, and Dyspnea (heart failure).
17. Flecainide and Propafenone are examples of which class of antiarrhythmic agents?
Explanation: They are Class Ic antiarrhythmics, which strongly block fast sodium channels, significantly slowing phase 0 depolarization. They are contraindicated in patients with structural heart disease.
18. What is considered the normal range for Left Ventricular Ejection Fraction (LVEF) on an echocardiogram?
Explanation: A normal resting LVEF is typically between 55% and 70%. Values below 50% generally indicate impaired systolic function.
19. Which serum biomarker is highly specific for the diagnosis and prognostic tracking of acute decompensated heart failure?
Explanation: BNP (and NT-proBNP) is released by the ventricles in response to volume expansion and pressure overload. It is an excellent marker for heart failure exacerbations.
20. What is the pharmacological mechanism of action of Clopidogrel?
Explanation: Clopidogrel is a thienopyridine prodrug that irreversibly blocks the P2Y12 component of ADP receptors on the platelet surface, preventing platelet aggregation.
21. A “granular sparkling” appearance of the myocardium on echocardiography with unexplained severe hypertrophy is highly suggestive of:
Explanation: The deposition of amyloid proteins between myocardial fibers creates an echogenic, granular “sparkling” or speckled texture classic for restrictive cardiomyopathy due to amyloidosis.
22. Statins (e.g., Atorvastatin) lower cholesterol primarily by inhibiting which enzyme?
Explanation: Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol biosynthesis. This leads to upregulation of LDL receptors and increased clearance of LDL from the blood.
23. In a patient with rapid atrial fibrillation but NORMAL left ventricular function, which medication class is considered a first-line option for rate control?
Explanation: Beta-blockers (like metoprolol) or non-dihydropyridine calcium channel blockers (like diltiazem) are first-line for rate control. Digoxin is a second-line option, and rhythm control agents (Amiodarone, Flecainide) are not used for pure rate control.
24. In the cardiac catheterization lab, the Fick principle is utilized primarily to calculate:
Explanation: The Fick principle states that blood flow to an organ (Cardiac Output) can be calculated using a marker substance (usually oxygen). CO = Oxygen consumption / (Arterial O2 content – Venous O2 content).
25. A wide and “fixed split” of the S2 heart sound, independent of the respiratory cycle, is the hallmark auscultatory finding of:
Explanation: In an ASD, the continuous left-to-right shunt delays pulmonic valve closure equally during both inspiration and expiration, causing a fixed, widely split second heart sound.