[Transvenous cardioversion in the treatment of sustained ventricular tachycardia. Preliminary results in 3 patients with implantable cardioverter].

The efficacy of intracardiac cardioversion was verified in 11 pts suffering from coronary heart disease and recurrent sustained VT. All pts were receiving anti-arrhythmic drugs. Tachycardia cycle length was between 280 and 400 msec. 65 episodes of VT (21 spontaneous and 44 induced) were treated with synchronized shocks of low energy between 0.27 and 2 J using the external cardioverter. Cardioversion was successful in 83% of VT episodes. VT acceleration occurred in one case; transient atrial fibrillation was induced six times. All pts tolerated shocks from 0.27 to 1 J with moderate discomfort; shocks exceeding 1.0 J were less well tolerated. CK levels were not increased. In three pts (VT cycle length of 320, 380 and 400 msec) a permanent Cardioverter (Medtronic Model 7210) was implanted and programmed to operate in non-automatic mode. Every month the pts underwent a follow-up visit to verify the electrophysiological features of VT in non invasively induced VT episodes and the efficacy of transvenous cardioversion. In a mean follow-up period of 9 months, respectively 5, 4 and 3 spontaneous VT episodes occurred. In two pts cardioversion resulted constantly effective, whereas in the third one provoked VT acceleration requiring DC-shock in the last spontaneous episode of VT.