Ventricular arrhythmia ablation timing and outcomes in electrical STORM requiring V-A ECMO support: the STORM-ECMO study

Electrical storm (ES) with refractory cardiogenic shock carries high mortality. While veno-arterial extracorporeal membrane oxygenation (V-A ECMO) may stabilize circulation, the role and timing of ventricular arrhythmia (VA) ablation under ECMO remain unclear. To assess the impact and optimal timing of VA ablation on ECMO weaning success in patients supported with V-A ECMO for ES-related refractory cardiogenic shock. We conducted a French multicenter retrospective cohort study including 218 patients treated between 2015 and 2023 in 9 tertiary centers. Patients requiring V-A ECMO for ES-related cardiogenic shock were included; 115 underwent VA ablation, and 103 did not. The primary endpoint was successful ECMO weaning, defined as liberation from ECMO alive without transition to durable mechanical circulatory support or heart transplantation 28 days after ECMO liberation. Analyses combined propensity-score matching, time-dependent Cox models, spline-based analysis, and landmark Fine & Gray competing-risk analyses to account for immortal time and competing events. VA ablation was associated with higher ECMO weaning success (cs-HR 1.72, 95% CI 1.08–2.73; p = 0.022). Spline-based Cox analysis indicated that the benefit was greatest when ablation was performed within the first days of support, progressively attenuating thereafter. Among ablated patients, early intervention (≤ Day 4) conferred a clear advantage over later ablation (HR 2.10, 95% CI 1.14–3.87; p = 0.01). A landmark Fine & Gray model confirmed a higher cumulative incidence of successful weaning with early ablation versus late or no ablation (sHR 2.23, 95% CI 1.26–3.87; p = 0.0045). In patients with ES-related refractory cardiogenic shock supported by V-A ECMO, VA ablation was associated with a higher probability of successful ECMO weaning, particularly when performed within the early days after cannulation.