Prognosis of patients undergoing catheter ablation of arrhythmic storm in patients with and without history of previous ICD interventions

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Catheter ablation (CA) improves prognosis in patients with electrical storm (ES). However, its effectiveness and timing in patients with ventricular tachycardia and appropriate ICD therapies remain a matter of debate. PURPOSE: Our aim was to investigate whether patients with history of discrete ventricular tachycardia episodes had different clinical features and outcome compared to patients with ES as first arrhythmic occurrence. METHODS: We enrolled 57 consecutive patients undergoing CA for ES and collected clinical, echocardiographic and electroanatomic mapping data. The primary end point was a composite of death from any cause and recurrences of sustained VT or ventricular fibrillation, appropriate ICD therapy, or ES. RESULTS: During a median follow up of 39 months, 28 patients (49%) met the primary end point of arrhythmic recurrence or death from any cause. There were no significant differences between clinical, electrocardiographic and echocardiographic parameters in the two groups. Regarding ICD therapies, patients with who met the primary end point had a higher number of ATP/shock episodes preceding the ES event: 15 (52%) vs 25 (89%), p=0.002. At Cox regression analysis, NIDCM, previous ATP and/or shock and ≥3 ATP were associated with arrhythmic recurrences and/or death. At multivariate analysis, ≥3 ATP was the only predictor that met statistical significance for the primary end point: HR was 30.41, CI 4.42 – 209.12, p=0.001. When dividing our population in patients and without ventricular arrhythmias (VAs) with appropriate device intervention before ES, thoses with VAs arrhythmias before ES had a higher percentage of presence of late potentials (80% vs 55%, p=0.041) and a greater unipolar scar (59.2±41.6 vs 30.2±21.6, p=0.001). At univariate analysis the presence of late potentials was associated with ventricular arrhythmias before ES (OR 3.33, CI 1.03-10.84, p=0.045). CONCLUSIONS: CA in patients with a long arrhythmia history, recurrent ICD therapies and presence of late potentials at electroanatomic mapping, may yield worse outcomes and therefore our results support an early referral for CA of VT to improve prognosis in these subjects.