Abstract
For the past 14 years, 179 leads for permanent pacing acre implanted with good initial stimulation thresholds. One hundred seventy-nine leads were divided into 3 groups according to their electrode surface area; i. e. group I, over 80mm313 leads, II, 80-15mm3, 57, III, less than 15mm3, 109. Actuarial survival curves were calculated in each group. Current threshold and voltage threshold at the time of implantation revealed good correlation between the electrode surface area and stimulation thresholds. However, lead longevity of these 3 groups, especially between II&III groups showed no correlation with electrode surface area. Actuarial analysis was used for detecting influencig factors on it. The analysis revealed followings bipolar leads, cylindrical metal tip leads, age at the implantation (over 60 years), basic cardiac disorders (hypertensive diseases, and congenital heart diseases), intracardiac R wave (more than 5mV) and energy ratio less than 81 at the initial implantation were significant influencing factors of the discrepancy between surface area and lead longevity in goup II and III.
