Answer: Intravenous magnesium, electical cardioversion or overdrive pacing, withdrawal of potentially QT prolonging medications and correction of the other electrolyte imbalances.
ACLS protocol should be initiated. Magnesium rapidly reverses polymorphic ventricular tachycardia and should be bolused at 2-4g of magnesium sulfate. The correction of other electrolyte abnormalities (hypocalcemia and hypokalemia) is also essential. Anti-tachycardia pacing (ATP) or overdrive pacing will frequently termintate polymorphic VT if magnesium and electrical cardioversion is not successful. A thorough medication review should identify all medications with potential QT prolonging affects and the should be discontinued.