Bipolar ablation of the left ventricular summit ventricular arrhythmias facilitated with microcatheter mapping of coronary veins

Introduction Bipolar radiofrequency (RF) ablation is an effective approach for treating refractory ventricular arrhythmias originating from the left ventricular (LV) summit. Venous mapping using a 2-French (2F) microcatheter can improve exact localization of ablation target and select the bipolar RF vector. This study aimed to compare procedural characteristics and long-term success rates of ablations performed with and without 2F venous mapping guidance. Methods This study is a subanalysis of a previously conducted multicenter study on bipolar ablation of ventricular arrhythmias. We retrospectively analyzed a subcohort of patients who underwent bipolar ablation of the LV summit. Patients were divided into two groups: those who underwent venous mapping with a 2F microcatheter to assess the earliest VA activation within the cardiac venous system, and those who did not. Key procedural parameters, including procedure duration, RF power, and application time, were compared. Long-term success was defined as freedom from arrhythmia during follow-up. Results A total of 68 patients (14 female, age 61±13, mean number of previous ablation: 2±1) were included in the analysis (2F catheter group: 11, non-2F group: 57). Bipolar RF power was significantly lower in the 2F-guided group (29±3W vs. 34±10W, p=0.03), while the RF application time remained comparable (373±262s vs. 399±306s, p = 0.89). The mean procedure duration was similar between groups (145±68min vs. 153±73min, p=0.58). In the 2F-guided group, complete arrhythmia elimination was achieved in 82% of patients, while 18% experienced no effect. In the non-2F group, complete elimination was observed in 77%, suppression in 12%, and no effect in 11%. No complications occurred in the 2F-guided group, whereas in the non-2F group, major complications included one anticipated atrioventricular block, one left anterior descending artery occlusion requiring angioplasty, one pericardial effusion, and one arteriovenous fistula treated conservatively. During follow-up lasting 7±8 months freedom from arrhythmia showed a trend favoring the 2F-guided group (92% vs. 70%), though statistical significance was not reached (p=0.094). Conclusions The use of a 2F catheter for venous mapping was associated with lower power settings without compromising procedural efficiency or long-term success. The trend toward improved arrhythmia-free survival suggests that precise arrhythmia localization achieved with 2F diagnostic microcatheter may optimize bipolar RF ablation outcomes and warrants further investigation.