Ablation of ventricular arrhythmia originating at the papillary muscle using an automatic pacemapping module

Background: Ventricular arrhythmia originating from the papillary muscle (VA-PM) is characterized by multiple exits and morphologic alternations. The conventional ablation strategy relies on activation mapping, but the results might be suboptimal.

Objective: The purpose of this study was to propose a novel pacemapping strategy aimed at multiple exits using high-output software as a complementary approach to the conventional strategy.

Methods: A consecutive 13 patients with VA-PM were enrolled in this study. Novel pacemapping based on an automatic matching algorithm and integrated electroanatomic mapping was used to quantify the morphology variation in these patients and to identify the potential exits of VA-PM. Complementary ablation targeting at the best matching site of each morphology was performed.

Results: Twelve of 13 patients (92%) experienced morphologic alternation, and a total of 34 morphologies were detected (2.6 ± 1.0 per patient). A total of 23 (68%) morphologies were detected as spontaneous pleomorphic ventricular premature complexes (VPCs) before procedure, and 4 morphologies (12%) were induced under isoproterenol infusion. Another 7 of 34 morphologies (21%) could be found only after radiofrequency ablation attempts. Exits with a high pacemapping correlation index for corresponding morphology would be mapped, so preferential exits could be identified. Mean interexit distance was 15.1 ± 5.9 mm. Acute success rate was 100%. During mean follow-up of 12.2 ± 6.9 months, only 1 case recurred with ventricular tachycardia. Although 3 cases recurred with different VPC morphologies, the VPC burden decreased from 16.3% ± 8.8% to 2.6% ± 1.7%.

Conclusion: This novel pacemapping strategy could effectively eliminate multiple exits as a complementary approach to the conventional strategy.