Endo-Epicardial Homogenization of the Scar Versus Limited Substrate Ablation for the Treatment of Electrical Storms in Patients With Ischemic Cardiomyopathy

Study Questions:

What is the most effective radiofrequency catheter ablation (RFCA) strategy for ventricular arrhythmias (VAs) in patients with electrical storm (ES)?

Methods:

Ninety-two patients (mean age 62 years) with ischemic cardiomyopathy (ICM; mean ejection fraction 27%) and ES (≥3 episodes of ventricular tachycardia in 24 hours) underwent either a conventional approach of endocardial mapping and ablation (group 1, n = 49) or endocardial and epicardial ablation of all potentials within scar (scar homogenization, group 2, n = 43). All patients had an implantable cardioverter-defibrillator (ICD). Arrhythmia recurrence during follow-up was defined as any VA that triggered an ICD therapy.

Results:

All patients in both groups underwent endocardial RFCA. Epicardial RFCA was performed in 8% of patients in group 1 and 33% of patients in group 2. The total procedure time was significantly longer in group 2 (4.8 vs. 3.6 hours), as was the radiofrequency time (74 vs. 39 minutes). There were no procedural complications. The mean duration of follow-up was 25 months. The VA recurrence rate was significantly higher in group 1 (47%) than in group 2 (19%). One patient in each group had a noncardiac death during follow-up.

Conclusions:

All patients in both groups underwent endocardial RFCA. Epicardial RFCA was performed in 8% of patients in group 1 and 33% of patients in group 2. The total procedure time was significantly longer in group 2 (4.8 vs. 3.6 hours), as was the radiofrequency time (74 vs. 39 minutes). There were no procedural complications. The mean duration of follow-up was 25 months. The VA recurrence rate was significantly higher in group 1 (47%) than in group 2 (19%). One patient in each group had a noncardiac death during follow-up.

Perspective:

Although this was not a randomized study, the results convincingly demonstrate the superiority of the scar homogenization approach for RFCA of scar-related VAs. Surviving myocytes within regions of scar serve as the substrate for reentrant VAs in patients with ICM. The goal of scar homogenization is to eliminate as many of these surviving myocytes as possible.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Endocardium, Cardiomyopathies, Catheter Ablation, Radio Waves


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