Appropriate and Inappropriate ICD Shocks in Patients with LVADS: Prevalence, Associated Factors, and Etiologies

Background Implantable cardioverter-defibrillator (ICD) shocks are a common complication following Left Ventricular Assist Device (LVAD) implantation; however, there is limited data on their frequency and causes. Objective To define the incidence, programming, patient characteristics, and factors associated with appropriate and inappropriate ICD shocks in persons with LVADs. Methods We performed a retrospective review at Duke University Hospital of all LVAD recipients implanted between January 1, 2013 to June 30, 2019 with a pre-existing ICD. ICD shocks were adjudicated by the treating physician and a 2nd reviewer for the purpose of this study. Results Among 421 patients with an ICD in situ undergoing LVAD implant, 147 (33.9%) patients had at least one shock following LVAD implantation. Among 134 patients with complete device history, there were a total of 330 shock episodes: 255 (77.3%) appropriate and 75 (22.7%) inappropriate. Etiologies for inappropriate shocks included SVT (n=66, 20.0%), physiologic oversensing (n=1, 0.3%), and non-physiologic oversensing (n=8, 2.4%) including LVAD electromagnetic interference (n=1, 0.3%). ICD programming with shorter detection delay (p < 0.001) and absence of anti-tachycardia pacing programming (p = 0.001) in high-rate zones was seen more commonly in inappropriate shock than appropriate shock. Conclusions The rate of inappropriate shocks in LVAD recipients is very high and is most often due to supraventricular arrhythmias. LVAD electromagnetic interference is a rare cause of ICD shock. Implementation of current consensus AHA recommendations for LVAD programming with long detection delays and high rate cutoffs may help avoid inappropriate ICD shocks.