Complete heart block — MCCQE Part 1 MCQ

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HardSyncopeComplete heart blockMCCQE Part 1

An 82-year-old man has recurrent syncope without prodrome; pulse is 34/min and ECG shows AV dissociation with a broad escape rhythm. Which of the following is the most likely diagnosis?

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Correct answer: E — Complete heart block

Complete heart block is the single best answer because the age, timing, examination findings and investigations in the vignette fit Complete heart block better than the alternatives. The most tempting distractor is less appropriate because it either treats a neighbouring presentation, delays a time-critical intervention, or ignores a key discriminator in the stem. The remaining options are suboptimal because they would miss the diagnosis, use an investigation or treatment in the wrong sequence, or fail to address safety and follow-up. Canadian practice should be anchored to CCS bradyarrhythmia guidance, with attention to acuity, safety-netting and local provincial pathways.

Reference: CCS bradyarrhythmia guidance