A randomized comparison of defibrillation thresholds in the right ventricular outflow tract versus right ventricular apex

Abstract

To determine whether the placement of an implantable cardioverter-defibrillator (ICD) lead in the right ventricular outflow tract (RVOT) has the same defibrillation threshold (DFT) as the right ventricular apex (RVA). Right ventricular ICD leads have usually been placed in the RVA. Development of active fixation technology has allowed the placement of these leads in alternate locations such as the RVOT. At time of device implantation, 26 patients with either ischemic or dilated cardiomyopathy underwent DFT testing in both the RVA and RVOT using a binary search algorithm. Placement of the lead in the RVA had a mean DFT of 7.6 +/- 2.8 J while the placement of the lead in the RVOT had a mean DFT of 10.3 +/- 3.0 J. The median (25th and 75th percentiles) DFTs in the RVA and RVOT were 7.5 J (6 and 11 J) and 11 J (9 and 14 J), respectively (p = 0.0002). Placement of the right ventricular lead in the RVA has a significantly lower DFT than placement of the lead in the RVOT.