Intraoperative Comparison of a Subthreshold Test Pulse with the Standard High-Energy Shock Approach for the Measurement of Defibrillation Lead Impedance
Article first published online: 29 NOV 2005
Journal of Cardiovascular Electrophysiology
Volume 17, Issue 1, pages 56–59, January 2006
How to Cite
SCHUCHERT, A., WINTER, J., BINNER, L., KÜHL, M., MEINERTZ, T. and on behalf of the Reliance Investigators (2006), Intraoperative Comparison of a Subthreshold Test Pulse with the Standard High-Energy Shock Approach for the Measurement of Defibrillation Lead Impedance. Journal of Cardiovascular Electrophysiology, 17: 56–59. doi: 10.1111/j.1540-8167.2005.00261.x
- Issue published online: 13 JAN 2006
- Article first published online: 29 NOV 2005
- Manuscript received 1 October 2004; Revised manuscript received 25 April 2005; Accepted for publication 31 May 2005.
- implantable cardioverter defibrillator;
- defibrillation test;
- defibrillation lead impedance;
- single-coil defibrillation lead;
- dual-coil defibrillation lead
There are two methods to measure shocking lead impedance: delivery of high-energy shocks that require patient sedation, and the painless measurement of impedance from subthreshold test pulses. The aim of this study was to compare the two methods.
Methods: The study included 131 patients implanted with a standard DR (n = 71) or VR (n = 60) ICD connected to either single-coil (n = 39) or dual-coil (n = 92) defibrillation leads. The noninvasive high-energy impedance test was done using a 17 J shock after induction of ventricular tachyarrhythmias and compared to a 0.4 μJ test pulse used by the ICD for the subthreshold measurements.
Results: Defibrillation lead impedance measurements were not significantly different between patients with the same shocking vector configuration. In patients with a single-coil defibrillation lead the impedance was 62 ± 9 Ω with the high-energy shock and 62 ± 8 Ω with the subthreshold test pulses (P = 0.13). Patients with a dual-coil configuration recorded average impedances of 40 ± 5 Ω from both tests (P = 0.44). While there was no difference in values recorded within each lead configuration, there was a significant difference in impedance between the single-coil and the dual-coil patient groups (P = 0.001).
Conclusions: There was no significant difference between shocking lead impedances measured with the high-energy shock or the subthreshold test pulses. This offers the possibility of noninvasive, low-energy serial measurements of shocking lead impedance at follow-up visits and removing the need for sedation.