Implantable cardioverter-defibrillator shocks in patients with a left ventricular assist device

Left ventricular assist device (LVAD) use is becoming increasingly common for patients with end-stage heart failure. However, the rate of implantable cardioverter-defibrillator (ICD) shocks and the effect of these shocks on outcomes in patients with LVADs remain unknown.

Medical records were reviewed from patients with both an ICD and a LVAD from September 2000 to February 2009. The association between ICD shocks and survival while receiving device support was assessed using Cox proportional hazards modeling.

Thirty-three of 61 patients with a LVAD also had an ICD and form the basis of this report. The mean duration of LVAD support was 238 days. One or more ICD shocks were delivered to 14 patients (42%) with 8 (24%) receiving appropriate shocks for ventricular arrhythmias and 6 (18%) receiving inappropriate shocks. No patients received both appropriate and inappropriate shocks. When compared with receiving no ICD shock, receiving any ICD shock or an appropriate ICD shock were both associated with an increase in the risk of death (hazard ratio [HR] 4.5, 95% confidence interval [CI] 1.2 to 17.3, p = 0.027, and HR 5.3, 95% CI 1.3 to 22.6, p = 0.023, respectively); receipt of an inappropriate shock showed a non-significant trend for an increased risk of death (HR 3.2, 95% CI 0.7 to 16.1, p = 0.151).

ICD shocks are common after implantation of LVADs, with nearly equal numbers of appropriate and inappropriate shocks. ICD shocks are associated with higher mortality. Larger studies are needed for assessing the independent relationship of ICDs to a variety of clinical outcomes in patients with LVADs.