The electrocardiographic QT interval and its prolongation in response to medications: differences between men and women.

Ventricular repolarization corrected for heart rate as measured by the electrocardiographic QTc interval differs in women compared to men. Although the mechanism remains unelucidated, the data are convincing that the effects of drugs that prolong ventricular repolarization are more likely to produce torsades de pointes arrhythmias in both healthy women and women with cardiac disease compared to men of similar ages and health status. Avoidance of such drugs and careful monitoring during necessary therapeutic administration of drugs that prolong ventricular repolarization is especially necessary in women. Electrolyte abnormalities such as hypokalemia and hypomagnesemia must be carefully avoided in patients receiving drugs that can produce QT prolongation. Because the recognition of this risk for drugs other than cardiac and psychotropic drugs has only recently emerged, it can be anticipated that the list of drugs known to produce such effects will grow.