Determinants and outcomes of late electrical storm in patients supported by left ventricular assist device

Although ventricular arrhythmias (VAs) are frequent after left ventricular assist device (LVAD) implantation, the characteristics and prognostic significance of late electrical storm (ES) remain incompletely understood.

This study aimed to assess the incidence and clinical impact of late ES in LVAD recipients.

This international, multicenter, retrospective study included 1151 LVAD recipients implanted between 2006 and 2019. Late ES was defined as ≥ 3 sustained VA episodes within 24 hours occurring beyond 30 days after implantation. The primary outcome was 5-year all-cause mortality. The secondary endpoint was 5-year cardiac mortality.

Late ES occurred in 49 patients (4.3%), with a median onset at 9.2 months after implantation. Patients with late ES experienced significantly higher 5-year all-cause mortality (adjusted hazard ratio [aHR] 2.87 [1.81-4.54]; P < .01) and cardiac mortality (aHR 3.47 [2.14-5.62]; P < .01). Notably, late VA without ES showed no prognostic impact. Multivariable analysis identified 4 independent predictors of late ES: left ventricular end-diastolic diameter of ≥80 mm before LVAD implantation (aHR 2.47 [1.29-4.87]), nonischemic cardiomyopathy (aHR 2.20 [1.10-4.40]), history of VAs (aHR 2.35 [1.27-4.32]), and implantable cardioverter-defibrillator before LVAD implantation (aHR 4.80 [1.12-20.85]). The late ES-LVAD score, based on these variables, demonstrated good discrimination (C-statistic 0.76) and stratified patients into low- (score 0-1), intermediate- (score 2-3), and high-risk groups (score 4-5), with corresponding late ES rates of 1.0%, 3.9%, and 7.8%.

Late ES, but not isolated late VAs, is independently associated with substantially worse long-term outcomes in LVAD recipients. The late ES-LVAD score enables practical risk stratification, facilitating targeted therapeutic interventions in high-risk patients.