CCT CCT Pharmacology & Cardiac Medications 1 — Questions and Answers
Question 1: Which class of drugs is used as first-line treatment to slow the ventricular rate in atrial fibrillation by blocking AV nodal conduction?
- Beta-blockers (Correct answer)
- Loop diuretics
- ACE inhibitors
- Thrombolytics
Correct answer: Beta-blockers
Beta-blockers decrease heart rate by blocking sympathetic stimulation at the AV node, making them first-line agents for rate control in atrial fibrillation.
Question 2: Atropine is administered during bradycardia primarily because it:
- Blocks vagal (parasympathetic) tone to increase heart rate (Correct answer)
- Increases potassium levels
- Decreases cardiac output
- Blocks calcium channels
Correct answer: Blocks vagal (parasympathetic) tone to increase heart rate
Atropine is an anticholinergic agent that blocks muscarinic receptors, thereby reducing vagal slowing of the heart and increasing the heart rate.
Question 3: Which antiarrhythmic drug is considered a Class III agent and is commonly used for ventricular and supraventricular arrhythmias?
- Amiodarone (Correct answer)
- Lidocaine
- Metoprolol
- Digoxin
Correct answer: Amiodarone
Amiodarone is a Class III antiarrhythmic that prolongs the action potential and refractory period and is used broadly for both ventricular and supraventricular arrhythmias.
Question 4: Nitroglycerin relieves angina primarily by:
- Dilating coronary arteries and reducing preload (Correct answer)
- Increasing heart rate
- Blocking beta receptors
- Raising blood pressure
Correct answer: Dilating coronary arteries and reducing preload
Nitroglycerin is a vasodilator that relaxes vascular smooth muscle, reducing preload and dilating coronary arteries to improve myocardial oxygen delivery.
Question 5: A patient receiving heparin infusion should be monitored primarily with which laboratory test?
- Activated partial thromboplastin time (aPTT) (Correct answer)
- Prothrombin time (PT)
- Complete blood count (CBC)
- Basic metabolic panel (BMP)
Correct answer: Activated partial thromboplastin time (aPTT)
Heparin's anticoagulant effect is monitored using the aPTT, with a therapeutic target typically 1.5–2.5 times the control value.
Question 6: Which electrolyte imbalance can potentiate digoxin toxicity and increase the risk of fatal arrhythmias?
- Hypokalemia (Correct answer)
- Hypernatremia
- Hypercalcemia
- Hypermagnesemia
Correct answer: Hypokalemia
Low potassium levels increase digoxin binding to Na+/K+-ATPase, greatly increasing its toxic effects and the risk of dangerous arrhythmias.
CCT CCT Pharmacology & Cardiac Medications 1
Which class of drugs is used as first-line treatment to slow the ventricular rate in atrial fibrillation by blocking AV nodal conduction?