CRAT Antiarrhythmic Medications and Clinical Interventions 2 — Questions and Answers
Question 1: Synchronized cardioversion is indicated for which of the following rhythms?
- Ventricular fibrillation
- Asystole
- Unstable supraventricular tachycardia with a pulse (Correct answer)
- Pulseless electrical activity
Correct answer: Unstable supraventricular tachycardia with a pulse
Synchronized cardioversion delivers a shock timed to the R wave and is used for unstable tachyarrhythmias with a pulse, avoiding accidental delivery during the T wave.
Question 2: What is the primary purpose of the 'synchronized' mode during cardioversion?
- To increase the energy delivered
- To prevent shock delivery during the vulnerable T wave period (Correct answer)
- To allow repeated shocks automatically
- To synchronize with the patient's breathing
Correct answer: To prevent shock delivery during the vulnerable T wave period
Synchronization ensures the shock is delivered on the R wave rather than the T wave, preventing the R-on-T phenomenon that could trigger ventricular fibrillation.
Question 3: Beta-blockers used as antiarrhythmics belong to which Vaughan Williams class?
- Class I
- Class II (Correct answer)
- Class III
- Class IV
Correct answer: Class II
Beta-blockers are Class II antiarrhythmics that reduce heart rate and AV nodal conduction by blocking beta-adrenergic receptors.
Question 4: Digoxin toxicity can cause which ECG changes?
- Peaked T waves and wide QRS
- Scooped ST depression and bradyarrhythmias (Correct answer)
- ST elevation in anterior leads
- Prolonged QT with U waves
Correct answer: Scooped ST depression and bradyarrhythmias
Digoxin toxicity classically causes scooped or 'Salvador Dali mustache' ST depression, bradyarrhythmias, and various AV blocks.
Question 5: Transcutaneous pacing is indicated as an emergency intervention for:
- Rapid atrial fibrillation
- Symptomatic bradycardia refractory to atropine (Correct answer)
- Ventricular fibrillation
- Asymptomatic first-degree AV block
Correct answer: Symptomatic bradycardia refractory to atropine
Transcutaneous pacing provides temporary electrical stimulation of the heart and is used for symptomatic bradycardia when atropine is ineffective.
Question 6: Which calcium channel blocker is primarily used to control ventricular rate in atrial fibrillation?
- Nifedipine
- Amlodipine
- Diltiazem (Correct answer)
- Nimodipine
Correct answer: Diltiazem
Diltiazem (a non-dihydropyridine calcium channel blocker) slows AV nodal conduction and is commonly used for rate control in atrial fibrillation.
CRAT Antiarrhythmic Medications and Clinical Interventions 2
Synchronized cardioversion is indicated for which of the following rhythms?