Appropriate and inappropriate ICD shocks in patients with LVADs: Prevalence, associated factors, and etiologies.

Background: Implantable cardioverter-defibrillator (ICD) shocks are a common complication after left ventricular assist device (LVAD) implantation; however, data on their frequency and causes are limited.

Objective: The purpose of this study was 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 preexisting ICD. ICD shocks were adjudicated by the treating physician and a second reviewer for the purpose of this study.

Results: Among 421 patients with an ICD in situ undergoing LVAD implant, 147 (33.9%) had at least 1 shock after LVAD implantation. Among 134 patients with complete device history, a total of 330 shock episodes occurred: 255 (77.3%) appropriate and 75 (22.7%) inappropriate. Etiologies for inappropriate shocks included supraventricular tachycardia (n = 66 [20.0%]), physiological oversensing (n = 1 [0.3%]), and nonphysiological oversensing (n = 8 [2.4%]) including LVAD electromagnetic interference (n = 1 [0.3%]). ICD programming with shorter detection delay (P <.001) and absence of antitachycardia pacing programming (P = .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 most often is due to supraventricular arrhythmias. LVAD electromagnetic interference is a rare cause of ICD shock. Implementation of current consensus American Heart Association recommendations for LVAD programming with long detection delays and high rate cutoffs may help prevent inappropriate ICD shocks.