NTA NTA Pharmacology and Medications 1 — Questions and Answers
Question 1: What is the primary cardiac action of atropine?
- Slows heart rate by increasing vagal tone
- Increases heart rate by blocking parasympathetic (vagal) tone (Correct answer)
- Lowers blood pressure by vasodilation
- Converts atrial fibrillation to sinus rhythm
Correct answer: Increases heart rate by blocking parasympathetic (vagal) tone
Atropine blocks the parasympathetic muscarinic receptors on the SA node, removing vagal slowing and increasing heart rate — making it the first-line drug for symptomatic bradycardia.
Question 2: Which drug is the first-line pharmacologic treatment for terminating supraventricular tachycardia (SVT)?
- Amiodarone
- Adenosine (Correct answer)
- Atropine
- Aspirin
Correct answer: Adenosine
Adenosine transiently blocks AV node conduction to interrupt the reentrant circuit driving SVT, and must be given as a rapid IV bolus due to its extremely short half-life.
Question 3: Which ECG finding is characteristic of digoxin toxicity?
- Prolonged PR interval and scooped ST depression (Correct answer)
- Shortened QT interval only
- Widened QRS complex with RBBB pattern
- ST elevation in all leads
Correct answer: Prolonged PR interval and scooped ST depression
Digoxin toxicity produces a prolonged PR interval and the classic scooped or 'Salvador Dali mustache' ST depression pattern on ECG.
Question 4: Amiodarone exerts its antiarrhythmic effect through which mechanism?
- Blocks sodium channels exclusively
- Blocks sodium, potassium, and calcium channels while also having beta-blocking properties (Correct answer)
- Stimulates the SA node to increase rate
- Increases sympathetic tone to stabilize rhythm
Correct answer: Blocks sodium, potassium, and calcium channels while also having beta-blocking properties
Amiodarone is a broad-spectrum Class III antiarrhythmic that blocks multiple ion channels and has alpha- and beta-blocking properties, making it effective for a wide range of arrhythmias.
Question 5: What is the first-line vasopressor used during ACLS for ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT)?
- Digoxin
- Epinephrine (Correct answer)
- Atropine
- Adenosine
Correct answer: Epinephrine
Epinephrine 1 mg IV every 3–5 minutes is the first-line vasopressor in the ACLS VF/pVT algorithm, improving coronary and cerebral perfusion pressure during resuscitation.
Question 6: How do beta-blocker medications affect heart rate?
- Increase heart rate by stimulating beta-1 receptors
- Have no measurable effect on resting heart rate
- Decrease heart rate by blocking beta-1 adrenergic receptors (Correct answer)
- Cause irregular heart rate through SA node suppression
Correct answer: Decrease heart rate by blocking beta-1 adrenergic receptors
Beta-blockers competitively block beta-1 receptors, reducing the response to catecholamines and lowering both resting and exertional heart rate.
NTA NTA Pharmacology and Medications 1
What is the primary cardiac action of atropine?