The Canadian journal of cardiology
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Review Comparative Study
Drug-induced long QT syndrome and torsade de pointes.
Several medications, including drugs prescribed for noncardiac indications, have been associated with a prolongation of the QT interval on the surface electrocardiogram. Under certain circumstances, this clinical manifestation may reflect an increased risk for patients presenting with a polymorphic ventricular tachycardia known as torsade de pointes. Drugs that prolong the QT interval belong to several pharmacological classes, but most of them share one pharmacological effect: they lengthen cardiac repolarization mostly by blocking specific cardiac K+ channels. ⋯ In brief, drug-induced torsade de pointes is a relatively rare event in the entire population, which nonetheless carries the risk of lethal consequences. Consequently, drug surveillance programs are very active in identifying drugs that induce the prolongation of the QT interval. Recent data have allowed us to better understand the underlying electrophysiological mechanisms of the syndrome and better identify predisposing factors.