Long-term outcome of verapamil-sensitive sustained left ventricular tachycardi in patients without structural heart disease

Objectives. This study attempted to determine the long-term outcome of verapamil-sensitive sustained left ventricular tachycardi in patients without apparent structural heart disease. Background. Several types of idiopathic ventricular tachycardi have been reported, and their clinical, electrophysiologic and electropharmacologic characteristics are different. It is possible that the prognosis of each type of ventricular tachycardi might also be different. Methods. We studied mortality and morbidity in 37 consecutive patients (27 male, 10 female; mean [± SD] age 33 ± 14 years) with verapamil-sensitive sustained left ventricular tachycardi who had no apparent structural heart disease. Patients were followed up for 1 to 13 years (mean 5.8). Verapamil repeatedly terminated ventricular tachycardi in all patients. Ventricular tachycardi originated from the inferior and inferoseptal regions of the left ventricle in 33 patients and the superior and superioseptal regions in 4. Severity of ventricular tachycardi was classified according to the extent to which symptoms limited daily activities. Ventricular tachycardi was mild (minimal limitation) in 14 patients, moderate (some limitation) in 17 and severe (severe limitation) in 6. Results. Fourteen patients with mild ventricular tachycardi were followed up without any drug therapy, and the ventricular tachycardi remained mild in all patients. Antiarrhythmic therapy was initiated empirically in the 23 patients with moderate and severe ventricular tachycardi (verapamil in 20, propranolol in 2, digoxin in 1). Moderate ventricular tachycardi became mild ventricular tachycardi after drug therapy in all patients, but the six patients with severe ventricular tachycardi showed no improvement. The six patients with severe ventricular tachycardi had nonpharmacologic therapy (cryosurgery in one, catheter ablation in four, antitachycardi pacing device in one). During the follow-up period, all patients remained alive except for one who died suddenly after implantation of an antitachycardi pacing device. Conclusions. 1) The long-term prognosis of verapamil-sensitive sustained left ventricular tachycardi in patients without apparent structural heart disease is good. 2) Verapamil is the drug of choice for alleviating symptoms, but nonpharmacologic therapy is necessary in some patients.