[Transvenous bidirectional shock with a triple electrode system: a promising step in the electrical management of ventricular tachyarrhythmias].

The aim of this work is to assess the reliability of transvenous high energy bi-directional shock with a triple electrode system as the initial step in implanting the automatic cardioverter defibrillator by thoracotomy. During the electrophysiological study on 12 patients, 16 different types of sustained ventricular tachycardia were treated with a 25 J bi-directional QRS synchronized shock delivered through a right ventricular apical cathode and 2 anodes, i.e., the superior vena cava-right atrium and skin patch electrode placed just above the left nipple. A Medtronic 6880 catheter, placed in the right ventricular apex, and a cutaneous patch (CRS, 50 cm2 in surface area) were connected by a cable to a Medtronic model 5350 external cardioverter defibrillator. All but one patient had coronary disease with previous myocardial infarction. The mean VT cycle length was 299 msec (min 200, max 380 ms); 5 VT types had left and 2 had right bundle branch block pattern; 9 had a "bizarre" pattern. The tachycardia was interrupted in 14 types; in 1 type (cycle length 360 msec with "bizarre" morphological pattern) ventricular fibrillation was induced by a well synchronized shock; in 1 type (cycle length 200 msec with "bizarre" morphological pattern) a badly synchronized shock induced a sustained ventricular tachycardia with a longer cycle length (360 msec); this was subsequently stopped by another shock. The transvenous high energy bi-directional shock was quite well tolerated by the patients.(ABSTRACT TRUNCATED AT 250 WORDS)