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Complete heart block with instability — RCPSC EM MCQ

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HardCardiovascular emergenciesComplete heart block with instabilityRCPSC EM

An 81-year-old has syncope, BP 76/42 mmHg and HR 28/min. ECG shows complete AV block with a wide escape rhythm. Atropine has had no effect; IV access and pacing pads are in place. What is the next step?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: C — Start transcutaneous pacing and prepare transvenous pacing

The best answer is “Start transcutaneous pacing and prepare transvenous pacing”. This is unstable high-grade bradycardia refractory to atropine. Transcutaneous pacing is the immediate bridge while expert support and temporary transvenous pacing are prepared. AV-nodal blockers and adenosine can worsen the bradycardia, while monitoring or discharge is unsafe in shock.

Reference: Heart & Stroke: 2025 resuscitation guideline highlights: https://cpr.heartandstroke.ca/resource/GuidelinesHighlightsGlance2025EN