Atrial Fibrillation Substrate and Catheter Ablation Outcomes in MYBPC3- and MYH7-Mediated Hypertrophic Cardiomyopathy

Area of Science:

• Cardiology
• Genetics
• Electrophysiology

Background:

• MYBPC3 and MYH7 genetic variants are linked to hypertrophic cardiomyopathy (HCM).
• The impact of these variants on atrial myopathy, atrial fibrillation (AF) clinical course, and catheter ablation outcomes is not well understood.
• Understanding the atrial substrate in these patients is crucial for optimizing treatment strategies.

Purpose of the Study:

• To investigate the atrial substrate in patients with MYBPC3- or MYH7-mediated HCM.
• To evaluate the efficacy of catheter ablation for AF in this patient population.
• To correlate genetic variants with atrial remodeling and ablation outcomes.

Main Methods:

• Retrospective single-center study of HCM patients undergoing genetic testing and AF ablation.
• Gene-positive cohort: MYBPC3 or MYH7 variants identified.
• Control cohort: No disease-causing genetic variants.
• High-density electroanatomical mapping and radiofrequency ablation were performed.

Main Results:

• Gene-positive cohort showed significantly higher percentages of low-amplitude (intermediate and dense scar) left atrial (LA) signals compared to controls.
• Despite increased fibrosis, freedom from AF at 12 months was similar between gene-positive (75%) and control (73%) cohorts.
• The gene-positive cohort required a greater number of procedures for rhythm control.

Conclusions:

• Patients with MYBPC3- or MYH7-mediated HCM exhibit increased LA fibrosis.
• Catheter ablation is an effective rhythm-control strategy for AF in this population.
• Further research may elucidate mechanisms linking genetic variants to atrial remodeling and guide personalized ablation strategies.