[Ablation of atrio-ventricular conduction by fulguration of the His bundle. Proposal for a simplified technic. Apropos of 70 cases].

Between 1982 and 1987, 70 patients (32 men, 38 women, aged from 45 to 93 years) underwent catheter ablation of His bundle and were followed up for more than 3 months. The disorders treated were atrial fibrillation, flutter of tachycardia (62 cases), junctional tachycardia (7 cases) and refractory atrial extrasystoles (1 case). The overall results were: early failure in 1 case, late death in 3 cases, persistent high degree AV block in 53 cases (75 p. 100), 1st degree AV block in 9 cases (12 p. 100) and failure in 8 cases (13 p. 100). Two techniques were used. In the first 30 patients ablation was performed by tri- or quadripolar catheters with electrodes 10 mm apart (USCI 2943/2854) and localization by an unipolar electrode connected to the negative pole of the defibrillator. The mid-term results in this series were: complete AV block in 20 cases (66 p. 100), partial AV block in 5 cases (17 p. 100) and failure in 17 cases (17 p. 100). In the last 40 patients localization was bipolar and ablation was obtained with simultaneous bipolar leads taken from a Josephson catheter with electrodes 5 mm apart (USCI 8567); the two electrodes recording the highest His bundle potential were connected to the negative pole of the defibrillator. The results in these series were: complete AV block in 33 cases (82 p. 100), partial AV block in 4 cases (11 p. 100) and failure in 3 cases (7 p. 100). Although the two series were not exactly similar, it seems permissible to recommend the second, more convenient technique.