Initial clinical experience with endocardial defibrillation using an implantable cardioverter/defibrillator with a triple-electrode system.
We evaluated the early clinical performance of an implantable cardioverter/defibrillator with a nonepicardial lead system in patients with refractory ventricular tachycardia or ventricular fibrillation. Ten patients, mean age 67 years, mean left ventricular ejection fraction 35%, refractory to 5 +/- 2 antiarrhythmic drugs and with a history of prior cardiac surgery (7 patients), severe lung disease (2 patients), or renal failure (1 patient) underwent device and lead system implant. A tripolar electrode catheter with one sensing electrode and two defibrillating electrodes was placed in the right ventricular apex and a left thoracic submuscular patch electrode was used in an epicostal location. Defibrillation energy threshold was determined using dual- or triple-electrode configurations. Optimal patch electrode location was determined after temporary use of a cutaneous patch electrode prior to cardioverter/defibrillator implant. Electrophysiologic studies were performed before discharge and after 2 to 3 months to assess device function. Percutaneous insertion and placement of the electrode catheter was achieved in all patients. Defibrillation energy threshold testing was done using 1 to 4 (mean, 2.7) electrode configurations per patient and required 6 to 21 (mean, 13) ventricular fibrillation inductions and 8 to 56 (mean, 22) shocks per patient. In all patients, lowest reliable defibrillation energy threshold was obtained with a triple-electrode configuration (right ventricular common cathode with right atrial and thoracic patch as dual anodes) and bidirectional shocks (mean, 18 +/- 5 J). Optimal patch electrode position could be determined in 9 of 10 patients, and these 9 patients had cardioverter/defibrillator implant. Ventricular fibrillation termination with the first delivered shock at electrophysiologic study was documented in all patients. There was no perioperative mortality in device-implanted patients. Postoperative electrophysiologic studies before discharge (9 patients) and at 3 months (8 patients) continued to demonstrate successful defibrillation by the first device shock. During follow-up (range, 2 to 10 months; mean, 6 +/- 3 months), spontaneous device discharges occurred in 4 patients with inappropriate shocks due to electrode catheter fracture being documented in 1 patient. Antiarrhythmic drug therapy was withdrawn in 6 patients and reduced in 3 patients. We conclude, based on our preliminary experience, that an implantable cardioverter/defibrillator can be successfully used with a nonepicardial lead system for endocardial defibrillation in many patients. This lead system can be used with currently available pulse generators and should be considered at cardioverter/defibrillator implantation. It can be anticipated to reduce patient risk and hospital costs associated with this procedure.
Saksena
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Division of Cardiology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark.
Tullo
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Krol
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Mauro
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D000368:Aged; D003327:Coronary Disease / Q000628:therapy*; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation*; D004566:Electrodes; D004594:Electrophysiology; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010138:Pacemaker, Artificial; D019736:Prostheses and Implants / Q000009:adverse effects; D013610:Tachycardia / Q000628:therapy*; D014693:Ventricular Fibrillation / Q000628:therapy*