Long-Term Outcome of Catheter Ablation of Electrical Storm due to Recurrent Ventricular Tachycardia in a Large Cohort of Patients with Idiopathic Dilated Cardiomyopathy

Background: Recurrent therapies due to monomorphic ventricular tachycardia (VT) in patients with implantable cardioverter-defibrillator (ICD) can adversely affect their long-term survival. We intended to evaluate the long-term effect of the catheter ablation of electrical storm due to monomorphic VT in patients with idiopathic dilated cardiomyopathy (DCM). Methods and Results: Between December 2006 and 2011, 40 consecutive patients (24 men, mean age 57.9 ± 13.6 years) with DCM and repeated monomorphic VT who had ICD underwent 70 radiofrequency catheter ablation procedures, including 23 epicardial (33%), at our center. After a median of 1.5 ablations, acute complete success was achieved in 22 patients (63%). During a mean follow-up of 820 days (range 238– 2120 days) 29 patients (72.5%) were free from VT recurrence. Compared to those without acute complete success (n = 18), in those with acute complete success (n = 22), 20 (90.9%) and 9 (50%) were free from any VT recurrence and ICD therapy, respectively (Fisher’s p = 0.005). During follow-up 2 (9.1%) and 4 (22.2%) patients died in the above mentioned groups, respectively (p = 0.267). Conclusion: Catheter ablation in DCM patients with electrical storm due to monomorphic VT prevents VT recurrence in 72.5% of the patients; however, many patients need more than one ablation procedure. Successful catheter ablation may play a protective role and was associated with a trend toward reduced mortality during the follow up period. More aggressive ablation strategies to ablate all inducible VTs improves long-term freedom from VT and probably survival in these patients.