Persistent myocardial ischemia after termination of dipyridamole-induced ventricular tachycardia by intravenous aminophylline: Scintigraphic demonstration

Ventricular tachycardia is a rare complication of dipyridamole stress testi ng. We present a case in which dipyridamole induced symptomatic ventricular tachycardia. The patient, a 41-year-old man with a history of chest discom fort on exertion for 1 year, underwent dipyridamole thallium imaging. Susta ined ventricular tachycardia occurred 1 minute and 40 seconds after complet ion of the dipyridamole infusion. Intravenous aminophylline (125 mg) was gi ven immediately and the tachycardia was terminated. Two minutes later, thal lium-201 was injected and subsequent myocardial imaging showed reversible p erfusion defects in the inferior wall, septum, and apex. Coronary angiograp hy revealed three-vessel disease. This case discloses that reversible perfu sion defects can still be demonstrated on thallium scan in spite of injecti on of aminophylline, an antagonist of dipyridamole, before thallium adminis tration.