Epicardial ventricular pacemaker electrode longevity in children.

While epicardially implanted electrodes remain the most widely used in children for ventricular pacing, their expected longevity remains unknown. The longevity of 126 such electrodes implanted from January 1970 through December 1985 was evaluated in 81 children followed up for 1 to 192 months (median 63). Age at initial implant was 1 day to 18 years. Each child had from 1 to 5 electrodes implanted; 85 electrodes were of the sutureless helical type and 41 were of the suture-fixated type. Electrode failure, defined as loss of capture with a high pacing threshold found at operation or sensing failure, occurred in 38 electrodes from 1 to 157 months postimplant (median 37). Mode of failure was high threshold with high impedance (n = 15), low impedance (n = 6), complete inability to pace (n = 8), sensing failure (n = 2) or high threshold with no measure of impedance (n = 7). Actuarial life table analysis of electrode longevity showed a 88 +/- 3% (standard error of the estimate) survival rate at 6 months with no significant decrease until 53 months (75 +/- 5%, p less than 0.05). There was then a gradual steady decrease to 49 +/- 7% by 101 months. From 101 to 157 months no significant decrease occurred. Survival rate decrease was greatest within the first 6 month period postimplant (-12%). Electrodes surviving to 6 months are highly likely to survive until 53 months. Of those surviving to 53 months, 74% should survive to 120 months.