Catheter Ablation for Ventricular Tachycardia in Patients With Hypertrophic Cardiomyopathy: Electrophysiological
Shuyu Jin1, Mengmeng Li1, Chenxi Jiang1
1Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Center for Cardiovascular Diseases, Beijing, China.
Insights
Catheter ablation for hypertrophic cardiomyopathy ventricular tachycardia (HCM-VT) primarily involves 3D re-entrant circuits. Success depends on identifying the VT origin and its intramural extent for effective ablation.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Catheter ablation for hypertrophic cardiomyopathy ventricular tachycardia (HCM-VT) is understudied, with limited data on VT distribution and electrophysiological characteristics.
- Existing research primarily focuses on feasibility and safety, leaving VT substrate and circuit properties insufficiently understood.
Purpose of the Study:
- To comprehensively characterize the site-specific electrophysiological properties of ventricular tachycardia (VT) in hypertrophic cardiomyopathy (HCM).
- To evaluate catheter ablation outcomes for HCM-VT based on detailed substrate and circuit analysis.
Main Methods:
- Inclusion of 32 patients with HCM-VT undergoing catheter ablation.
- Utilized combined endocardial and epicardial mapping to identify and analyze arrhythmogenic substrates and re-entrant circuits.
- Induced and mapped 28 VTs across 25 patients to understand circuit mechanisms.
Main Results:
- The majority of VTs (25/28) were scar-mediated re-entries, predominantly located in the left ventricular (LV) lateral wall, apical aneurysm, and superior basal regions.
- Incomplete activation sequences were observed, indicating complex re-entrant pathways with mid-myocardial involvement.
- Long-term VT-free survival varied by VT origin, with superior basal regions and septum showing 0% survival, while LV lateral wall and apical aneurysm had higher rates (73.3% and 83.3% respectively) after initial ablation.
Conclusions:
- HCM-VT commonly presents as three-dimensional re-entrant circuits with significant mid-myocardial involvement.
- Successful catheter ablation is contingent upon accurately identifying the VT re-entrant circuit's origin and its extent of intramural penetration.
Background:
Studies on catheter ablation of hypertrophic cardiomyopathy (HCM)- ventricular tachycardia (VT) are relatively limited and mainly focused on feasibility and safety, whereas the VT distribution and electrophysiological properties remain insufficiently characterized.
Objectives:
The aim of this study was to detail the site-specific electrophysiological properties and ablation outcomes in HCM-VT.
Methods:
A total of 32 patients with HCM-VT who underwent catheter ablation were included. Through endocardial and epicardial mapping, their arrhythmogenic substrate and re-entrant circuit were identified and analyzed.
Results:
Combined endocardial/epicardial mapping was performed in 29 of the 32 patients. Twenty-eight VTs were induced among 25 patients, including 25 scar-mediated re-entries, 2 focal origins, and one bundle branch re-entry. Twenty-five re-entries were localized to the left ventricular (LV) lateral wall (9 of 25), apical aneurysm (6 of 25), superior basal regions (8 of 25), interventricular septum (1 of 25), and papillary muscle (1 of 25), respectively. Incomplete activation sequences were recorded across regions: LV lateral wall (epicardium: 54.3% ± 11.7%; endocardium: 35.9% ± 15.5%), apical aneurysm (endocardium: 40.3% ± 25.0%; epicardium: 32.7% ± 22.6%), and superior basal regions (endocardium: 25.5% ± 7.7%; epicardium: 27.2% ± 11.4%). Over a median follow-up of 31 months, the long-term VT-free survival rate after the index procedure was 73.3% in the LV lateral wall, 83.3% in the apical aneurysm, and 0% in the LV superior basal region and septum, which was consistent with the extent of mid-myocardial involvement. The VT-free survival rate after multiple procedures was 71.9% in all patients.
Conclusions:
HCM-VTs were primarily three-dimensional re-entrant circuits with mid-myocardial involvement. Procedural success largely depended on the origin and extent of intramural involvement of VT re-entry.
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