High incidence of atrial lead insulation failure in sub-pectoral defibrillator pockets

Abstract

Implantable defibrillators (ICD) were routinely placed in a sub-pectoral muscle site at our institution prior to the year 2000. We have noted a high incidence of atrial lead insulation failures at the time of re-operation for generator changes in these patients (pts). To date 39 pts have undergone device re-operation: mean age 68 years, 35 male, mean duration of implant 55 months. All were dual chamber (DDD) ICDs. Pre-operative atrial lead problems were suspected in some pts due to reproducible oversensing “noise” with pectoral muscle movement (n=5) or high “atrial tachycardia response” counts (n=5). At operation 24 atrial leads (62%) were found to have visible areas of insulation breakdown with conductor coil exposed. The affected leads were predominantly Guidant “Sweet Tip”, models 4054 (n=10), 4244 (n=8), 4269 (n=5) and a Medtonic model 4254 (n=1). Insulation breakdown consisted of both areas of apparent abrasion and also splits in the insulation, usually at bend points. Sometimes more than 1 insulation defect was present. In 16 cases the lead was repaired using a Guidant repair kit and re-used. Eight leads were abandoned and new atrial leads placed. Only 1 ventricular lead (Guidant model 0155) showed damage. All leads (atrial and ventricular) were removed from the sub-pectoral site and implanted subcutaneously with the replacement ICD generator. We conclude that sub-pectoral DDD ICD’s are associated with a high rate of atrial lead insulation failure, especially in Guidant “Sweet Tip” leads, during follow-up. This incidence may relate to the “harsh environment” of the lead location between the ICD and the chest wall. Physicians should be alert to the potential for this problem when following these pts. Further studies need to clarify if this insulation damage is unique to particular leads or a general problem with the sub-pectoral site.