EFFECT OF THE ADDITION OF AN ABDOMINAL HOT CAN CARDIOVERTER DEFIBRILLATOR PULSE-GENERATOR ON THE DEFIBRILLATION ENERGY-REQUIREMENTS IN A SINGLE-LEAD ENDOCARDIAL DEFIBRILLATION SYSTEM/

Aims The effects of a cardioverter/defibrillator system with an electr ically active generator can, applied without recourse to thoracotomy, have not been investigated in the abdominal position in humans. The pu rpose of this acute clinical study was to evaluate the defibrillation efficacy of an abdominally positioned hot can electrode in connection with a single lead endocardial defibrillation system. Patients and Met hods Thirty consecutive patients undergoing implantation of a cardiove rter/defibrillator or pulse generator replacement were enrolled in thi s study. Each patient received an integrated, tripolar single-lead sys tem. This was tested using an asymmetrical biphasic defibrillation wav eform with constant energy delivery. Defibrillation energy, peak volta ge, peak current and impedance were compared between two electrode con figurations; (A) in this configuration the distal right ventricular co il was negative and the proximal coil positive; (B) in this configurat ion the distal right ventricular coil was negative and the proximal co il and the abdominal hot can (65 ccm), as common anode, were positive. Defibrillation threshold testing started at 15 J with stepwise energy reduction(10 J, 8 J, 5 J and 3 J) until defibrillation was ineffectiv e.Results Compared to the single-lead configuration, the abdominal hot can configuration revealed at 17.5% reduction in defibrillation energ y requirements (8.6 J +/- 4.3 J vs 10.43 J +/- 3.9 J; P=0.041), a 15.7 % reduction in peak voltage (308.6V +/- 63V vs 365.3V +/- 68V; P=0.003 ), and a 21.6% reduction in impedance (41.1 Omega +/- 6.3 Omega vs 52. 4 Omega +/- 6.6 Omega; P<0.001). Peak current showed a significant inc rease during hot can testing of 8.2% (7.2 A +/- 1.8 A vs 7.8 A +/- 2.2 A; P=0.16). Conclusion An abdominally placed hot can pulse generator lowered defibrillation energy requirements in patients with an endocar dial defibrillation lead system.