1‐Year Performance of a Defibrillation Lead with a Small Electrode Surface for High Impedance Pacing: A Randomized, Controlled Study

Abstract

A small electrode surface reduces pacing current drain and can extend generator longevity. The study evaluated the performance of a tined, quadripolar defibrillation lead (model 6944) that has a small-surfaced, steroid-eluting electrode tip for high impedance pacing. In a prospective, controlled study, 34 patients with conventional ICD indications were randomized one to one to receive the high impedance model 6944 or a tined defibrillation lead with a conventional sized, steroid-eluting electrode tip model 6942. Lead performance was evaluated at implant, prior to hospital discharge, and 1, 3, 6, and 12 months thereafter. Baseline characteristics did not differ significantly between patients implanted with lead model 6942 (n = 16) or model 6944 (n = 17). One patient randomized to receive the model 6942 was excluded from the study and was implanted with an active-fixation lead after stable lead positioning was neither possible with the 6942 nor with the 6944 electrode. No other lead related adverse events were observed. At implant, there were no significant differences between pacing thresholds, sensing performance, defibrillation impedances, and defibrillation thresholds in both groups, but pacing impedance of the model 6944 (988.6 +/- 217.7 omega) was approximately twice as high as high as in the model 6942 (431.7 +/- 83.7 omega; P < 0.0001). This difference remained highly significant throughout the observation period of 12 months, while R wave amplitudes and pacing thresholds remained equal in both lead models. The use of a tined defibrillation lead with a small, steroid-eluting electrode tip appears safe and results in a high pacing impedance without compromising system performance.

Long‐Term Performance of Transvenous, Steroid‐Eluting, High Impedance, Passive‐Fixation Ventricular Pacing Leads

“…Initial experience by Joglar et al 5 also suggested the possibility of a higher threshold when high impedance electrode was used. This study and several other studies have demonstrated stable electrical performance of high impedance electrodes during follow‐up 7–10,15,16 . The current drain was reduced by the high impedance leads and the battery longevity was extended 11,12 …”

Automatic Impedance Monitoring and Patient Alert Feature in Implantable Cardioverter Defibrillators:

“…In a recent study by Dorwarth et al, lead survival decreased from 98% at 4‐year follow‐up to only 62% at 8‐year follow‐up 5 . Newer defibrillation leads have a better overall clinical performance in the short term 6–8 . In any case, lead system failure places patients with ICDs at risk for delivery of inappropriate shocks and may even result in sudden cardiac death.…”

“…5 Newer defibrillation leads have a better overall clinical performance in the short term. [6][7][8] In any case, lead system failure places patients with ICDs at risk for delivery of inappropriate shocks and may even result in sudden cardiac death. Measurements of pacing and high-voltage impedance are routinely performed during outpatient ICD visits, but intermittent discontinuity in lead conductor integrity can be difficult to detect or confirm.…”