Drink, drugs, and the QT interval.

The effects of several prescription and illicitly-used drugs on electrocardiographic repolarization are well documented, most frequently manifested as prolongation of the corrected QT (QTc) interval. The combination of multiple repolarization-modulating drugs taken in high dosage can occasionally lead to extreme abnormalities of the QTc interval and ST-segment on the surface ECG, which can lead to the erroneous diagnosis of underlying myocardial ischemia and inappropriate treatment. We report on one such case in which the acute management of a syncopal patient was detrimentally influenced by misinterpretation of a very unusual ECG.