Abstract

BACKGROUND: Bipolar radiofrequency catheter ablation (B-RFA) has shown promising results in refractory ventricular arrhythmias (VAs) of septal origin and underlying non-ischemic cardiomyopathy. However, its efficacy and safety in other locations, such as papillary muscles (PM) or with different underlying substrates has yet to be fully determined. OBJECTIVE: To describe the procedure data, safety, and efficacy of B-RFA in a cohort of patients with VAs of different locations and underlying substrates and to generate new hypotheses. METHODS: We prospectively enrolled 26 patients with VAs, of whom 21 ultimately underwent B-RFA during the ablation procedure. Of these, 17 were redo procedures. Thirteen patients presented ventricular tachycardia (VT), and eight patients had ventricular ectopy (VE). Procedure data, related complications and acute and long-term outcomes during follow-up were assessed. RESULTS: Of the 21 patients, 76.2% were male, and the mean age was 60.8 ± 15.4 years. Fourteen patients had underlying substrate, and 7 had no structural heart disease. The VA originated from the septum (n = 9), lateral wall (n = 7), and PM (n = 5). Acute success, defined as the absence of the clinical VE or non-inducibility of VT at the end of the procedure, was achieved in 20 patients (95.2%). At 12-month follow-up, 8 (61.5%) patients with VT did not present any sustained arrhythmia or ICD therapy, and 6 (75%) patients with VE had a > 90% reduction in their burden on the 24-h Holter. Papillary muscle VAs seemed to present lower acute and long-term success after B-RFA. The use of B-RFA in PM, compared to other cardiac locations, required a greater number of radiofrequency applications (p = 0.010) with lower mean contact force (p = 0.001) and impedance drop (p = 0.010). No major peri-procedural complications were observed. CONCLUSIONS: Bipolar RF delivery can be used safely and successfully for VAs of septal and free wall origin but may have more limited use for PM arrhythmias. In this location, B-RFA exhibits reduced energy transfer, as does conventional ablation. No differences in procedural data or outcomes of B-RFA are observed based on the underlying substrate.