Causes of redo procedures in patients with an implantable cardioverter-defibrillator--long-term follow-up results.

BACKGROUND Implantation of a cardioverter-defibrillator (ICD) is a well-established method to prevent sudden cardiac death (SCD). Due to the expanding indications for this type of treatment and increasing survival of these patients, the ICD population is growing rapidly. AIM To assess the rate and causes of reoperations in patients with ICD over a long-term (at least 4 years) follow-up period. METHODS Between 1995 and 2006, an ICD was implanted in 598 patients. This study included all patients with a follow-up duration of at least 4 years and only those who underwent a repeat procedure later than 6 weeks after the index ICD implantation. RESULTS The study group consisted of 174 patients with a mean age of 51+/-18 years who were followed for a mean of 6+/-1.7 years. Coronary artery disease (CAD) was diagnosed in 92 (53%) patients, and non-ischaemic cardiomyopathy in 82 (47%) patients. Prophylactic ICD therapy was instituted in 11 (6%) patients, whereas 163 (94%) patients received ICD for secondary prophylactics. During the follow-up period, 10 deaths occurred: 6 of all deaths (60%) in patients with CAD and 4 of all deaths (40%) in the non--ischaemic group. A total of 211 redo procedures in 139 patients were performed. Indications for repeat procedures included battery depletion in 136 patients, ICD malfunction in 37 cases, infection related to the implanted system in 5 patients, problems with leads in 19 cases, an upgrade to the dual-chamber system in 5 or to the biventricular system in 3 patients, and the revision of an ICD pocket in 6 patients. CONCLUSIONS Repeat procedures in ICD recipients are frequent. The most common cause is battery depletion and ICD replacement indicated by a manufacturer. Improvement in ICD technology is essential to increase ICD longevity and decrease the redo-procedure rates. Patients with ICD should be regularly followed in experienced centres in order to detect ICD system failure early.