Characteristics and Outcome of Patients with or without Previous Implantable Cardioverter Defibrillator Interventions Undergoing Ablation for Ventricular Tachycardia.

Background: Catheter ablation (CA) is a well-established treatment in patients with ventricular tachycardia and appropriate implantable cardioverter defibrillator (ICD) therapies. Methods: We enrolled 57 consecutive carriers of ICD undergoing CA for electrical storm (ES). Our aim was to investigate differences in clinical, device-related, and electroanatomic features among patients who had history of appropriate ICD interventions before the ES compared to those who had not. The primary endpoint was a composite of death from any cause and recurrences of sustained VT, ventricular fibrillation, appropriate ICD therapy, or ES. Results: During a median follow up of 39 months, 28 patients (49%) met the primary endpoint. Those with previous ICD interventions had a higher prevalence of late potentials and a greater unipolar low-voltage area at electroanatomic mapping. Patients who met the primary endpoint had a higher prevalence of ATP/shock episodes preceding the ES event. At Cox regression analysis, non-ischemic dilated cardiomyopathy (NIDCM), QRS duration, and previous ATP and/or shock before the ES were associated with arrhythmic recurrences and/or death. At multivariate analysis, NIDCM and previous shock were associated with arrhythmic recurrences and/or death. Conclusions : A history of recurrent ICD therapies predicts worse outcomes when CA is needed because of ES. Although more studies are needed to definitively address this question, our data speak in support of an early referral for CA of ES.