Successful treatment of stress-induced therapy refractory ventricular tachycardia with verapamil

A 51-year-old woman was admitted to the hospital for further elucidation of a syncope of unknown origin and exercise-induced tachycardias with broad QRS-complex. The tachycardia was induced by bicycle exercise stress testing, had a frequency of 165/min, showed an inferior axis and left bundle branch block. Organic heart disease was excluded by right and left heart catheterization and selective coronary angiography. A nodoventricular bundle or an atrio-ventricular bundle was excluded by an extensive electrophysiologic study, therefore the documented tachycardia was probably of ventricular origin. However, it was not possible to induce a ventricular tachycardia by programmed ventricular stimulation with up to three extrastimuli even after the infusion of isoprenaline. Sotalol (2 x 160 mg/die) and the combined treatment with mexiletine (2 x 360 mg/die) and disopyramide (2 x 250 mg/die) did not prevent the induction of the tachycardia by exercise testing. The combination of sotalol and flecainide (2 x 100 mg/die) evoked complex ventricular arrhythmias at rest not noted before, and it was therefore withdrawn as well. After all antiarrhythmic drugs were withdrawn verapamil was given in a dose of 3 x 120 mg and this therapy reproduceably prevented the induction of ventricular tachycardia by exercise testing.