Abstract 16532: Dual Coil Transvenous Cardioverter Defibrillator System Have Lower Defibrillation Thresholds and Impedances Compared to Single Coil Systems: A Meta-Analysis
Introduction: Defibrillation efficacy and energy requirements have progressively decreased with the advent of bi-phasic shock technology and active can systems. Further attempts at improvement led to dual coil defibrillator leads (DCL) but there is paucity of studies and data regarding the performance of these leads in comparison to traditional single coil leads (SCL).
Methods: We performed a meta-analysis of published studies comparing DFT and shock impedance in DCL and SCL. Pubmed, Embase and Cochrane Central were searched with the following search terms: ICD leads, dual coil ICD, single coil ICD. Studies were included if they prospectively compared transvenous DCL (integrated or two separate leads) and SCL, using a full DFT testing protocol or a binary protocol. Studies were excluded if they were retrospective, had non-pectoral implantation, if the second coil was implanted in locations other than the SVC, compared atrial defibrillation thresholds or compared effects of different locations of the proximal coil on DFT. Data was extracted on an intention-to-treat basis. Heterogeneity of the studies was analyzed by Cochran’s Q statistics. A random effect model was used for stringency to combine studies.
Results: Eight studies with 1308 patients were included in the analysis. Four had a cross over design. Studies were homogeneous with a I-sqaure of 0% and a p=0.61. DCL systems had a lower DFT compared to SCL systems (Mean difference -0.85J, standard mean difference -0.19J, 95% CI -0.29 to 0.08, p<0.01, Fig). They also had lower shock lead impedances (Mean difference -16.5ohms, standard mean difference -2.24 ohms, 95% CI -2.54 to -1.94 ohms).
Conclusion: Our findings show that DCL systems have a lower DFT and impedances compared to SCL. Whether this advantage in energy translates into clinical outcomes is yet unknown and should be investigated.
- © 2013 by American Heart Association, Inc.