Identification and catheter ablation of a zone of slow conduction in the reentrant circuit of ventricular tachycardia in humans.

Three patients who had incessant ventricular tachycardia and in whom a zone of slow conduction was identified are presented. Each patient's tachycardia was refractory to multiple antiarrhythmic drugs and was being treated with amiodarone at the time of the electrophysiologic study. The ventricular tachycardia cycle length was 500 to 580 ms. In Patients 1 and 2, a single site at the posterolateral wall or low septum in the left ventricle was identified at which overdrive pacing during ventricular tachycardia resulted in ventricular capture with a stimulus to QRS interval of 280 to 400 ms and with little or no change in the configuration of the QRS complexes during pacing as compared with during ventricular tachycardia. In Patient 3, the same phenomenon was observed at two areas in the left ventricle: at the inferior wall, overdrive pacing during ventricular tachycardia resulted in a stimulus to QRS interval of 440 to 470 ms, whereas at the posterolateral wall, the stimulus to QRS interval was 320 to 360 ms. Transcatheter shocks of 100 to 240 J delivered at the pacing sites have been successful in preventing recurrences of ventricular tachycardia over a follow-up period of 10 to 11 months. These observations may be explained by the pacing site being located within a reentrant circuit in a zone of slow conduction bounded by inexcitable tissue between the pacing site and the exit site of the reentrant circuit. In Patient 3, the variable stimulus to QRS intervals are explained by variable proximity of the pacing sites within the slow conduction zone to the exit site of the reentrant circuit.(ABSTRACT TRUNCATED AT 250 WORDS)

[Endocavitary fulguration in the treatment of cardiac arrhythmia]. / La fulguration endocavitaire dans le traitement des arythmies cardiaques.

Fulguration of the heart cavities seems currently to be a technique of increasing value in the treatment of untractable arrhythmias, of supraventricular junctional or ventricular origin. This study represents the evaluation of our experience with 64 patients, maximum follow-up is 54 months and the minimum follow-up is 7 months. Although the results are quite satisfactory in the fulguration of the bundle of his and in the fulguration of the arrhythmic site inducing ventricular tachycardia, these results are inferior in the Wolff-Parkinson-White syndrome in which fulguration of the coronary sinus seems contraindicated al filter (LEM type), resulting in the death of the patient. It is a true, early (1st week) migration after accurate positioning, opposite L4, and not an incident of insertion.