Prognostic Value of Antiarrhythmic Drug Suppression of Electrical Storm Prior to Ventricular Tachycardia Ablation

Introduction: Early ablation after electrical storm (ES) has been associated with improved ventricular tachycardia (VT)-free survival. Antiarrhythmic drugs (AAD) can acutely temper ES in some patients allowing for delayed elective ablation, but they may be ineffective in other patients, who may require urgent ablation. The prognostic impact of acute AAD efficacy for ES patients undergoing ablation is unclear and may help to inform timing of VT ablation. The purpose of our study is to compare the outcomes of patients with ES undergoing VT ablation based on acute AAD efficacy. Methods: This retrospective study of patients with ES who underwent VT ablation at our institution between November 2018 and September 2023 compared those who underwent urgent ablation due to inefficacy of AAD (Urgent) versus those in whom AAD controlled ES acutely and ablation could be performed in an elective manner (Elective). The timing of ablation was based on provider discretion and ability to control ES on AAD. Long term survival, VT-free survival, ES-free survival and repeat ablation-free survival were compared through Kaplan Meir analysis and the log-rank test. Individual predictors of survival and VT-free survival were identified through Cox proportional hazards model with univariate and multivariate regression analysis. Results: One hundred and twenty patients were included (n = 68 urgent, median 7 days postepisode of ES vs. n = 52 elective, median 86 days post ES). Major complications were significantly higher in the urgent group (17.7% vs. 3.9%, p = 0.023). The Elective group had significantly improved long-term survival at time of follow up (χ² = 7.4, p = 0.0065). There were no significant differences in VT-free, ES-free survival or repeat ablation-free survival. Cox multivariate regression indicated significantly increased mortality in the Urgent group (p = 0.039), but no difference in VT recurrence (p = 0.88). An increased number of inducible VT foci during ablation was significantly associated with increased mortality. Use of B-blockers was associated with decreased rates of VT recurrence. Conclusion: Patients with ES who were able to be electrically stabilized with AAD and returned for an elective ablation had improved survival compared to those who required urgent ablation, although there were no differences in VT and ES recurrence rates. Stabilization with AAD before VT ablation is a positive prognostic factor for survival in ES.