CVT CVT Pharmacology & Cardiac Medications 1 — Questions and Answers
Question 1: Which class of antiarrhythmic drugs works primarily by blocking sodium channels to stabilize cardiac cell membranes?
- Class I (Correct answer)
- Class II
- Class III
- Class IV
Correct answer: Class I
Class I antiarrhythmics (e.g., lidocaine, flecainide) block fast sodium channels, slowing conduction velocity and stabilizing excitable membranes.
Question 2: Adenosine is used in the clinical setting primarily to:
- Convert atrial fibrillation to sinus rhythm
- Terminate paroxysmal supraventricular tachycardia (Correct answer)
- Increase heart rate in bradycardia
- Reduce preload in heart failure
Correct answer: Terminate paroxysmal supraventricular tachycardia
Adenosine transiently blocks AV nodal conduction to terminate reentrant SVT, restoring sinus rhythm within seconds.
Question 3: Which anticoagulant is most commonly used during cardiac catheterization to prevent thrombus formation?
- Warfarin
- Heparin (Correct answer)
- Dabigatran
- Rivaroxaban
Correct answer: Heparin
Unfractionated heparin is the standard anticoagulant for procedural anticoagulation during cardiac catheterization due to its rapid onset and reversibility.
Question 4: Nitroglycerin relieves angina primarily by:
- Increasing myocardial oxygen supply via coronary vasoconstriction
- Reducing preload and afterload through venous and arterial dilation (Correct answer)
- Blocking beta-adrenergic receptors
- Increasing cardiac contractility
Correct answer: Reducing preload and afterload through venous and arterial dilation
Nitroglycerin is a nitrate that donates nitric oxide, causing smooth muscle relaxation, venodilation, and reduced preload, decreasing myocardial oxygen demand.
Question 5: A patient receiving digoxin therapy develops nausea, visual disturbances, and bradycardia. The CVT should suspect:
- Anaphylaxis
- Digoxin toxicity (Correct answer)
- Pulmonary embolism
- Hypertensive crisis
Correct answer: Digoxin toxicity
Classic digoxin toxicity presents with GI symptoms, visual changes (yellow-green halos), and bradyarrhythmias due to enhanced vagal tone and decreased AV conduction.
Question 6: Beta-blockers are contraindicated in patients with which of the following conditions?
- Stable angina
- Decompensated heart failure (Correct answer)
- Post-MI management
- Hypertension
Correct answer: Decompensated heart failure
Beta-blockers are contraindicated in acute decompensated heart failure because negative inotropy can worsen cardiac output and precipitate cardiogenic shock.
CVT CVT Pharmacology & Cardiac Medications 1
Which class of antiarrhythmic drugs works primarily by blocking sodium channels to stabilize cardiac cell membranes?