Catheter ablation of electrical storm due to monomorphic ventricular tachycardia in patients with nonischemic cardiomyopathy: acute results and its effect on long-term survival

Background: Electrical storm due to recurrent ventricular tachycardia (VT) in patients with implantable cardioverter defibrillator (ICD) can adversely affect their long-term survival. This study evaluates the efficiency of the radiofrequency catheter ablation of electrical storm due to monomorphic VT in patients with idiopathic dilated cardiomyopathy (DCM) and assesses its long-term effects on survival.

Methods and results: Between April 2004 and October 2008, 13 consecutive patients (nine men, mean age 56.8 ± 17.8 years) with DCM and electrical storm due to monomorphic VT who had ICD underwent 17 catheter ablation procedures, including four epicardial, at our center. Acute complete success was defined as the lack of inducibility of any VT at the end of procedure during programmed right ventricular stimulation and was achieved in eight patients (61.5%). During a median follow-up of 23 months (range 3-63 months) nine patients (69%) were alive and eight patients (61.5%) were free from VT recurrence. Among those with acute complete (n = 8) and partial (n = 5) success, seven patients (87.5%) and one patient (20%) were free from any VT recurrence and ICD therapy, respectively (P = 0.025). Among those with acute complete and partial success, seven patients (87.5%) and two patients (40%) were alive, respectively (Mantel-Cox test P = 0.082). Among those who had an initially failed endocardial ablation (n = 8), four underwent further epicardial ablation that was completely successful in three patients (75%).

Conclusion: Catheter ablation in patients with DCM and electrical storm due to monomorphic VT who had an ICD prevents further VT recurrence in 61.5% of the patients. Complete successful catheter ablation may play a protective role and was associated with reduced mortality during the follow-up period. More aggressive ablation strategies in patients with initially failed endocardial ablation might improve the long-term survival of these patients; however, further studies are needed to clarify this issue.