Patients Experiencing Unsuccessful Defibrillation From Implantable Cardiac Devices Remain at Elevated Risk Despite Procedural Management.

BACKGROUND

Unsuccessful defibrillation therapy in patients with implantable cardiac defibrillators (ICDs) and ventricular tachytherapies may occur due to patient and/or device-related factors; appropriate management strategies after failed defibrillation therapy have been incompletely described.

OBJECTIVES

To report on the management and outcomes of patients with implantable cardiac devices and unsuccessful defibrillation therapies.

METHODS

A single-center cohort of patients with ICDs was examined, patients with unsuccessful ICD therapies were included. Demographic and device features, and survival free from recurrent unsuccessful device therapy was examined among patients undergoing operative vs. non-operative management.

RESULTS

Among 1449 patients with ICDs, 40 patients (2.8%) were identified with unsuccessful defibrillation therapies (mean age 59 ± 15 years, ejection fraction 29% ± 16%, ischemic cardiomyopathy n = 27, 67.5%, secondary prevention device placement n = 22, 55%, transvenous ICD n = 34, 85%, subcutaneous ICD n = 6, 15%). Nonoperative management strategies included device reprogramming (n = 8), addition of a class III anti-arrhythmic (n = 7), or conservative therapy (n = 5). Operative management included addition of a transvenous lead (n = 10), addition of subcutaneous array (n = 8), or change in pulse generator (n = 2). A single-coil device was present in 18/20(90%) patients undergoing operative management compared to 10/20 (50%) with non-operative management (p = 0.16). There were no demographic or device differences between the two groups. After 2.4 ± 2.1 years follow up, repeat VT occurred in 22 patients (55%) including 6 patients (15%) with a repeat failed defibrillator therapy. There was no differences in the risk of recurrent failed shocks among patients with operative vs non-operative management (log rank p = 0.14).

CONCLUSIONS

Among a large cohort of patients with ICD, the incidence of failed defibrillator therapy was 2.8%. With appropriate patient selection, both operative and non-operative management led to similar long-term outcomes; however, the overall incidence of repeat failed defibrillation therapy remained high at 15%.