[Treatment of recurrent ventricular tachycardia with hydroquinidine. Evaluation of its efficacy with electrophysiological technics].

Electrophysiological investigations were used to test the efficacy of dihydroquinidine chlorhydrate (600 or 1 200 mg/day) in a prospective study of 18 patients with recurrent ventricular tachycardia documented by electrocardiography. These patients did not respond to an average of 3.1 +/- antiarrhythmic drugs, including amiodarone in 12 patients. Hydroquinidine was well tolerated in 17 patients but had to be withdrawn in 1 patient because of hypotension. The effect of hydroquinidine on ventricular tachycardia induced by programmed pacing was evaluated after a 48 to 72 hours treatment, 3 to 5 hours after the last dose. After hydroquinidine it was not possible to induce ventricular tachycardia in 10 patients (58.8%). In the other 7 patients, it was possible to induce a ventricular tachycardia under treatment. In one case, hydroquinidine aggravated the arrhythmia as the induced tachycardia had a shorter cycle. In the other patients, hydroquinidine lengthened the tachycardia cycle by an average of 94 +/- 79 ms. The right ventricular refractory period increased cycle by 44 +/- 23 ms. Long-term hydroquinidine was prescribed for 7 patients, twice in association with amiodarone. Relapse was observed in 2 patients, 1 and 5 months after the onset of treatment. Five patients were well controlled by the treatment. The results of this study demonstrate the efficacy of hydroquinidine for the prevention of tachycardia induced by stimulation and underline its value in the treatment of sustained, recurrent ventricular tachycardia. This study illustrates the illustrates the importance of electrophysiological techniques for the identification of patients likely to benefit from a given antiarrhythmic treatment.