Intracoronary Acetylcholine-Induced Prolongation of the QT Interval and Torsade des Pointes in Long QT Interval Syndrome

Abstract

A 75-year-old female had syncopal episodes from Torsade des Pointes (TdP). Her electrocardiogram showed a prolonged QT interval which was not associated with electrolyte imbalances or drug therapy. Similar electrocardiographic abnormalities were found in three family members. Electrophysiologic study showed a mildly prolonged effective refractory period of 260'290 msec, but no tachyarrhythmia was induced. Coronary arteriography was normal but intracoronary acetylcholine unexpectedly induced a prolongation of the QT interval and TdP. Direct action of acetylcholine on the ventricular muscle was suggested. (Jpn Heart J 35: 683-688, 1994). © 1994, International Heart Journal Association. All rights reserved.