NREMT Paramedic Cognitive ExamCardiology & ResuscitationMedium
A 30-year-old male presents with palpitations, lightheadedness, and a heart rate of 190 bpm. His blood pressure is 100/70 mmHg, and he is alert but anxious. The ECG shows a regular, narrow-complex tachycardia. After attempting vagal maneuvers without success, what is the MOST appropriate next intervention?
- ADiltiazem 0.25 mg/kg IV
- BAdenosine 6 mg rapid IV push
- CAmiodarone 150 mg IV over 10 minutes
- DSynchronized cardioversion 50 J
Show answer & explanationAnswer & explanation
Correct answer: B. Adenosine 6 mg rapid IV push
This patient has a stable, regular, narrow-complex tachycardia that did not respond to vagal maneuvers. According to ACLS guidelines, the next step for a stable patient in this scenario is adenosine 6 mg rapid IV push. Adenosine temporarily blocks AV nodal conduction, often terminating re-entrant supraventricular tachycardias.
Why the other options are wrong
- A. Diltiazem (a calcium channel blocker) can be used for rate control in stable narrow-complex tachycardias, but adenosine is preferred for conversion of re-entrant SVT.
- C. Amiodarone is typically used for ventricular arrhythmias or refractory SVT, not as a first-line drug for stable narrow-complex tachycardia.
- D. Synchronized cardioversion is for unstable patients or those refractory to medications.
Stable Narrow-Complex Tachycardia Refractory to Vagal Maneuvers
For a stable patient with regular, narrow-complex tachycardia that does not convert with vagal maneuvers, the next intervention is adenosine, a rapid-acting medication that briefly blocks AV nodal conduction.
- Patient must remain stable (no signs of hypoperfusion).
- Adenosine is given as a rapid IV push, followed by a saline flush.
- Common side effects include brief asystole, flushing, chest discomfort.
- If adenosine is ineffective, a second dose of 12 mg can be given.
Memory trick: Vagal Failed? Adenosine's the Aim!