Safety and Efficacy of Cryoablation for Right Ventricular Moderator Band-Papillary Muscle Complex Ventricular Arrhythmias

BACKGROUND The right ventricular moderator band and papillary muscle (RV MB-PM) complex is an uncommon source of ventricular arrhythmias (VAs). Success rates following the ablation of intracavity structures are lower than for other sites of origin of VAs because of challenging catheter stability and a tendency for hemodynamically unstable automaticity when radiofrequency (RF) is delivered. OBJECTIVES This study sought to describe the institutional experience of RV MB-PM VAs across a 2-year period and compare the outcomes from ablations performed using RF ablation and cryoablation. METHODS Electronic health records of patients who underwent catheter ablation of RV MB-PM arrhythmias between January 2018 and November 2021 were reviewed, including imaging, intraprocedural data, and follow-up. RESULTS Eleven patients underwent ablation of RV MB-PM arrhythmias throughout the duration of the study. Five patients underwent catheter ablation with RF, and 6 patients underwent cryoablation. Three patients in the cryoablation group had previous attempted ablation with RF. Four patients in the RF group and 4 patients in the cryoablation group had structurally abnormal hearts. Acute VA suppression was achieved in 4 of 5 patients with RF and 6 of 6 patients with cryoablation. During follow-up, the rate of arrhythmia recurrence was lower in the cryoablation group (HR: 0.12; 95% CI: 0.016-0.90; P= 0.0396). CONCLUSIONS Compared to RF, cryoablation offers improved catheter stability and reduced propensity for automaticity during ablation. The use of cryoablation as a first-line strategy is reasonable when RV MB-PM origin of premature ventricular contractions is suspected. (C) 2022 by the American College of Cardiology Foundation.

Automated summary

The right ventricular moderator band and papillary muscle complex is an uncommon source of ventricular arrhythmias. This study reviewed the institutional experience of RV MB-PM arrhythmia ablation and compared the outcomes of RF ablation and cryoablation. The results showed that cryoablation offered improved catheter stability and reduced propensity for automaticity during ablation.