Background: Data about VT ablation in patients with electrical storm (ES) is limited. This study sought to compare the prognostic outcome of patients with ischemic cardiomyopathy to those with non-ischemic cardiomyopathy undergoing VT ablation on mortality, VT recurrence rates, rehospitalization rates and major adverse cardiac events (MACE).

Methods: In this large single-centre study patients presenting with ES and undergoing VT ablation were included from June 2018 to April 2021. Patients with ischemic cardiomyopathy were compared to patients with non-ischemic cardiomyopathy. The primary prognostic outcome was cardiovascular mortality, secondary endpoints were VT recurrences, rehospitalization rates and MACE all after a median follow-up of 22 months.

Results: A total of 108 patients underwent a first VT ablation due to electrical storm and were included (65  13 years; 86% male; 45% ischemic cardiomyopathy). Cardiovascular risk factors such as arterial hypertension, diabetes mellitus and hyperlipidaemia were increased among ICM patients (all p<0.001). Major complications occurred rarely (p>0.05 for all complications). Noninducibility of the clinical VT was achieved in 92% of ICM patients and in 96% of NICM patients. Noninducibility of any VT was achieved in 77% of ICM patients and in 75% of NICM patients (all p>0.05). Non-invasive programmed stimulation was performed in 29% of all patients and here equally in 40% of all ICM and NICM patients any VT could be induced (p>0.05). After 1 year and a median of 22 months follow-up, both groups reveal equal cardiovascular mortality (log-rank p=0.987). VT recurrence during follow-up was 54% in ICM and 73% in NICM patients (log rank p=0.037). In univariate analysis the hazard ratio for VT recurrence in ICM patients was significantly decreased compared to NICM patients (HR 0.533; CI 95% 0.293 – 0.972; p=0.040). Independent predictors of favourable outcome regarding VT recurrence in multivariable regression analysis were betablocker therapy (HR 0.046; p=0.035) and ICM (HR 0.278; p=0.021). Rehospitalization rates (log rank p=0.867) and rates of MACE (log rank p=0.414) were equal.

Conclusions: Although short-term success rates and cardiovascular mortality after VT ablation in electrical storm patients with ICM and NICM were similar, NICM patients revealed worse long-term VT recurrence rates.