Magnesium and Arrhythmia Risk

Magnesium is not simply another electrolyte result to correct after the urgent work is finished. It helps stabilise ventricular electrical activity, and a deficiency can make a prolonged QT interval more likely to degenerate into torsades de pointes (TdP), a potentially fatal polymorphic ventricular tachyarrhythmia. The bedside question is therefore not “Is the magnesium low?” but “Is this patient showing a prolonged-QT rhythm pattern, a precipitating cause, or deterioration in perfusion?” A patient with new palpitations, light-headedness, syncope, or ventricular ectopy deserves a focused rhythm and medication assessment before routine care continues. If TdP is present, intravenous magnesium sulfate is first-line pharmacologic treatment for the acute episode and helps prevent recurrence when the QT interval is prolonged. Treatment of the precipitating electrolyte disturbance and removal of avoidable triggers are addressed at the same time.