COMPATIBILITY OF A NONTHORACOTOMY LEAD SYSTEM WITH A BIPHASIC IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR

This prospective multicenter study was conducted under the Food and Dr ug Administration investigational Device Exemption to evaluate the saf ety and efficacy of the combination of the Cadence(R) implantable defi brillator (Ventritex, Inc.) and 60-series Endotak(R)C leads (Cardiac P acemakers, Inc.). implantation was attempted in 148 patients with hemo dynamically compromising ventricular tachycardia or fibrillation (VF), or with pace-terminable ventricular tachycardia. The system wets succ essfully implanted in 97% of patients, with 96% of implants in a trans venous-lead-alone configuration. At implantation, the defibrillation t hreshold was 455 +/- 94 V (14 +/- 61) for lead-alone patients and 532 +/- 40 V (19 +/- 3 J) for those requiring a subcutaneous patch. VF con version efficacy was reconfirmed in patients who underwent a 3-month c hronic induction study. The system successfully detected all 763 induc ed arrhythmias and terminated 99.5% of them; after system modification , successful conversion was demonstrated in the 2 patients wile initia lly had induced episodes requiring external defibrillation (1 lead rev ision; 1 reprogramming). All spontaneous episodes were terminated with an implantable-cardioverter defibrillator. Postshock VF redetection t imes were significantly shorter than initial detection times (4.5 +/- 1.8 seconds detection, 2.1 +/- 0.7 seconds redetection; p < 0.0001). D uring an 8-month mean follow-up (range 1 to 31 months), 2 unwitnessed deaths were classified as sudden cardiac deaths, and 11 patients exper ienced a total of 12 complications, none of which was associated with the Cadence-Endotak combination.