Abstract
One hundred and ninety nine myocardial pacing leads were followed up to 26yrs. and their survival probability was reviewed with special reference to lead failure. The survival probability of myocardial leads was compared with that of 1640 endocardial leads. The survival probability (SP) was calculated with Kaplan-Meier method and compared with generalized Wilcoxon test. The SP of myocardial leads was 89%, 79% and 68% at 5, 10 and 15-26yrs, respectively. The mean survival of myocardial leads was 20.2 yrs. The SP of endocardial leads was 83% and 72% at 10 and 20-22 yrs, respectively. Myocardial leads had a significantly poorer survival than endocardial leads (p=0.01). Among myocardial leads no difference of SP was found by models. The average voltage threshold of 104 myocardial leads (Medtronic model 6917) at implant was 0.86V at 0.5msec and that of 180 endocardial leads (Medtronic model 4024) was 0.37V. Myocardial leads had significantly higher voltage thresholds than endocardial leads at implant. From the point of durability and energy saving pacing we recommend to use endocardial leads as a first choice at the permanent pacemaker implantation.
