CMT CMT Pharmacology and Cardiac Medications 1 — Questions and Answers
Question 1: Which class of antiarrhythmic drug works by blocking sodium channels and is used to treat ventricular arrhythmias?
- Class IA/IB/IC agents (Correct answer)
- Class II beta-blockers
- Class III potassium channel blockers
- Class IV calcium channel blockers
Correct answer: Class IA/IB/IC agents
Class I antiarrhythmic drugs (IA, IB, IC) block sodium channels, slowing conduction velocity and treating ventricular arrhythmias.
Question 2: Amiodarone is classified as which class of antiarrhythmic medication?
- Class I
- Class II
- Class III (Correct answer)
- Class IV
Correct answer: Class III
Amiodarone is a Class III antiarrhythmic that primarily blocks potassium channels, prolonging the action potential and refractory period.
Question 3: Which medication is the first-line treatment for symptomatic bradycardia caused by increased vagal tone?
- Amiodarone
- Adenosine
- Atropine (Correct answer)
- Lidocaine
Correct answer: Atropine
Atropine is the first-line drug for symptomatic bradycardia as it blocks muscarinic receptors to increase heart rate.
Question 4: A patient receiving digoxin develops bradycardia with first-degree AV block. The cardiac monitor technician should alert the nurse because this may indicate:
- Therapeutic drug level
- Digoxin toxicity (Correct answer)
- Hypokalemia effect only
- Normal drug response
Correct answer: Digoxin toxicity
Bradycardia and AV block in a patient on digoxin are classic signs of digoxin toxicity requiring immediate clinical intervention.
Question 5: Which electrolyte imbalance most significantly increases a patient's risk of digoxin toxicity?
- Hypernatremia
- Hypercalcemia
- Hypokalemia (Correct answer)
- Hypermagnesemia
Correct answer: Hypokalemia
Hypokalemia enhances digoxin binding to Na+/K+-ATPase, increasing toxicity risk even at therapeutic drug levels.
Question 6: Adenosine is the drug of choice for terminating which arrhythmia?
- Atrial fibrillation
- Paroxysmal supraventricular tachycardia (PSVT) (Correct answer)
- Ventricular fibrillation
- Torsades de pointes
Correct answer: Paroxysmal supraventricular tachycardia (PSVT)
Adenosine transiently blocks AV nodal conduction, effectively terminating reentrant SVT that involves the AV node.
CMT CMT Pharmacology and Cardiac Medications 1
Which class of antiarrhythmic drug works by blocking sodium channels and is used to treat ventricular arrhythmias?