Ineffective implantable cardioverter-defibrillator shocks among patients on continuous left ventricular assist device support: Clinical characteristics and management

BACKGROUND: Placement of a left ventricular assist device (LVAD) has been described to compromise implantable cardioverter-defibrillator (ICD) defibrillation threshold (DFT). Elevated DFT will have negative consequences and increases the risk of ineffective ICD shocks, morbidity, and mortality. DFT testing is not routinely performed in clinical practice, despite this fact. OBJECTIVE: We describe the clinical characteristics of 7 LVAD patients who presented with multiple ineffective ICD shocks, along with the management strategy in such patients. METHODS: Seven patients (5 male, mean age 52.2 ± 9 years, 85.7% nonischemic cardiomyopathy) with an ICD in situ who progressed to NYHA class IV, ACC/AHA stage D chronic systolic congestive heart failure who underwent successful LVAD implantation presented to our institution in the setting of ventricular tachyarrhythmia and ineffective ICD shocks. Six patients underwent implantation of azygos and subclavian coils with subsequent DFT testing. The remaining patient was made comfort care. RESULTS: Five patients had successful DFT testing with azygos (n = 4) and subclavian (n = 1) defibrillation coil implantation. One patient had unsuccessful DFT testing despite evaluation of multiple shock vectors. There were no major or minor vascular complications in any of the cases. There were no procedural-related deaths. CONCLUSION: This case series highlights the need for a systematic approach to management of ICDs and DFT testing in LVAD patients. The addition of new shock vectors with azygos and subclavian coil implantation may reduce DFT, shock burden, morbidity, and mortality.