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Torsades de pointes — RCPSC EM MCQ

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ModerateCardiovascular emergenciesTorsades de pointesRCPSC EM

CTAS 1. A 68-year-old collapses in the ED after vomiting for 2 days. Monitor shows polymorphic VT with waxing QRS amplitude. BP is 88/46 mmHg and QTc on the earlier ECG was 560 ms. Potassium is 2.9 mmol/L and magnesium is 0.55 mmol/L. What is the most appropriate initial management?

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

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Correct answer: A — IV magnesium sulfate

Torsades de pointes associated with prolonged QT is treated with IV magnesium and correction of electrolytes, with cardioversion if pulseless or highly unstable.

Reference: ACLS Provider Manual; Canadian Cardiovascular Society arrhythmia resources