RESUMEN
BACKGROUND: Dual-coil implantable defibrillator (ICD) leads with true bipolar pacing and sensing (quadripolar leads) have been introduced to provide improved sensing characteristics without sacrificing defibrillation efficacy. Electrode configuration has been shown to have little effect on the amplitude or slew rate of the intracardiac electrogram, but does have an effect on the duration of the sensed electrogram. Closer spacing of the electrodes and smaller surface area of the anode may, therefore, result in a different latency of sensing relative to the onset of the QRS complex. METHODS: We tested the difference in ventricular sensing latency between integrated bipolar and true bipolar electrode configurations in 40 patients undergoing ICD implantation for standard indications (Medtronic Sprint Quattro lead in 26 and St. Jude Riata in 16). In addition, we compared R wave amplitude, pacing threshold, impedance, and slew rate. RESULTS: Sensing latency was significantly longer in the true bipolar configuration (Medtronic Sprint Quattro 45.2 +/- 14.7 msec in the true bipolar configuration, vs 37.4 +/- 18.2 msec in the integrated bipolar configuration, and St. Jude Riata, 43.5 +/- 9.8 msec true bipolar, vs 33.8 +/- 10.1 msec integrated bipolar, P < 0.01). There was no difference in R wave amplitude or slew rate. Pacing threshold and impedance were also greater in the true bipolar configuration than in the integrated bipolar configuration. CONCLUSION: The true bipolar configuration has a longer sensing latency than the integrated bipolar configuration. In some patients, this may require a longer programmed AV delay to avoid ventricular pseudofusion.
Asunto(s)
Desfibriladores Implantables , Arritmias Cardíacas/terapia , Análisis de Falla de Equipo , Femenino , Humanos , Masculino , Estudios Prospectivos , Diseño de PrótesisRESUMEN
Over the past decade, four randomized, controlled trials have evaluated therapies for prevention of sudden cardiac death in patients with coronary disease. Three of the four trials have shown significant reductions in mortality with implanted defibrillators. Two studies failed to demonstrate any benefit from pharmacologic antiarrhythmic therapy. The results of these studies in similar patient populations have erased any doubt regarding the ability of implanted defibrillators to reduce the risk of sudden death in patients with coronary disease. Our major challenge at this time is understanding how best to utilize this therapy in order to bring the benefit to the maximum number of patients while minimizing expense.