Pulsed electric field ablation for perimitral flutter - retrospective comparison of anterior vs lateral mitral block strategy

Abstract

Abstract Introduction Catheter ablation of atrial fibrillation has become a standard of care for symptomatic patients. Patients with persistent atrial fibrillation might require additional substrate modification on top of pulmonary vein isolation. In case of spontaneous or inducible perimitral flutter, RF ablation to achieve anterior or lateral mitral block is challenging. A pulsed electric field (PEF) is a novel energy source that enables the rapid and safe creation of larger lesions. Purpose A retrospective study aimed to compare the safety and early outcome data of either anterior or lateral mitral block strategy performed by PEF using a pentaspline multipolar ablation catheter. Methods The population consists of 67 patients (23 women, age: 68 ± 8 years) with either spontaneous or inducible perimitral flutter. Fifty-five percent of patients had previous ablation of atrial fibrillation using radiofrequency energy (2.0 ± 1.2 procedures/patient). Using a pentaspline multipolar catheter, all patients underwent isolation (or reisolation) of pulmonary veins and posterior wall. The same catheter was used for the treatment of perimitral flutter. Creating either anterior (ANTERIOR group) or lateral (LATERAL group) mitral block was selected at the discretion of the operator. Results A total of 37 and 30 patients were treated in the ANTERIOR and LATERAL groups, respectively. The perimitral flutter was terminated in all cases. However, complete and persistent block across the ablated region was more likely achieved in the ANTERIOR vs LATERAL group (92 vs 73%, p=0.04). There was one tamponade in the ANTERIOR group. A clinically relevant spasm of the coronary artery was not observed in any patient. At 3-month follow-up, non-significantly more patients were in sinus rhythm in the ANTERIOR vs LATERAL group (81% vs 63%, p=0.1). Conclusion Creating both anterior and lateral mitral block for the treatment of perimitral flutter is feasible and safe using a pentaspline multipolar catheter and PEF. Achievement of the anterior mitral block is more likely. Whether this will impact the long-term outcome remains to be determined.