A 60-year-old male presents with sudden onset of dizziness, weakness, and syncope. His ECG shows a regular rhythm with a heart rate of 30 bpm, wide QRS complexes, and no discernible P waves. He is hypotensive with a blood pressure of 80/50 mmHg. Which of the following is the most appropriate initial intervention?
- AAdminister atropine 0.5 mg IV push.
- BAdminister adenosine 6 mg IV push.
- CPrepare for transcutaneous pacing.
- DPerform synchronized cardioversion.
Show answer & explanationAnswer & explanation
Correct answer: C. Prepare for transcutaneous pacing.
The patient presents with symptomatic bradycardia (HR 30 bpm, hypotension, dizziness, syncope) with a wide QRS complex and no P waves, indicative of a ventricular escape rhythm or third-degree AV block with a wide QRS. Atropine is less likely to be effective for wide-complex bradycardia originating below the AV node. Transcutaneous pacing is the most appropriate initial intervention for symptomatic bradycardia unresponsive to atropine or when atropine is unlikely to be effective.
Why the other options are wrong
- A. Atropine is the first-line drug for symptomatic bradycardia, but it often works on the SA/AV node. A wide QRS bradycardia suggests a ventricular origin or complete block below the AV node, where atropine may be less effective.
- B. Adenosine is used for narrow-complex tachycardias, not symptomatic bradycardia.
- D. Synchronized cardioversion is used for unstable tachyarrhythmias, not bradycardia.
Symptomatic Bradycardia Management
Symptomatic bradycardia is a heart rate less than 60 bpm causing signs/symptoms of decreased cardiac output (e.g., hypotension, altered mental status, syncope).
- Identify bradycardia and associated symptoms.
- First-line drug: Atropine (if effective for level of block).
- If atropine ineffective or wide QRS, prepare for transcutaneous pacing.
- Dopamine or epinephrine infusions are alternatives if pacing is delayed or ineffective.
Memory trick: Slow Heart, Low Pressure, Pace it Now!