Atrial substrate and electrogram characterization in patients with atrial fibrillation and hypertrophic cardiomyopathy
G Mascia, S Viani, J Ramos-Maqueda, M Millesimo, G Dell'era, M Anselmino, G Tola, D Bianco, J Melero-Polo, P Sartori, M Malacrida, P Matcovich, G Zucchelli, P Di DonnaAbstract
Background
Data on left atrial (LA) electroanatomical substrate and electrogram (EGM) characteristics in patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF) remain limited.
Purpose
We sought to characterize LA substrate properties in patients with HCM and paroxysmal AF.
Methods
CHARISMA is a prospective, single-arm, post-market cohort study. Consecutive HCM patients from 7 Italian and Spanish centers undergoing ablation for paroxysmal AF were propensity matched with non-HCM patients with AF, and their LA substrate characteristics and outcomes were compared. Three-dimensional LA geometry was reconstructed using the Orion catheter and the Opal Mapping System (Boston Scientific), and the LA was divided into 34 anatomically distinct regions, including the left and right pulmonary veins (PVs), posterior wall, and anterior wall. The Lumipoint (Boston Scientific) map-analysis tool was sequentially applied to each LA region, and intracardiac EGMs were extracted from the Opal mapping system for offline analysis.
Results
Thirty patients (15 with HCM and 15 controls) were included. Baseline demographics, atrial size, and valvular disease prevalence were comparable between HCM and control patients. Patients with HCM exhibited significantly larger intermediate to low-voltage areas (ILVA; bipolar voltage <0.8 mV) as a proportion of total LA area (19.0 ± 8% vs 12.6 ± 6%, p = 0.024) and a higher percentage of fragmented EGMs (8.2 ± 4% vs 4.7 ± 3%, p = 0.015). Regions with ILVAs were more frequently observed in HCM patients compared with controls (46.5% vs 35.7%, p < 0.001), particularly around the left PVs (58.1% vs 41.0%, p = 0.019), posterior wall (46.1% vs 34.5%, p = 0.043), and anterior wall (29.6% vs 17.8%, p = 0.031). Regions with fragmented EGMs were also more prevalent in HCM patients (27.5% vs 16.9% of regions, p < 0.001), most prominently around the left PVs (28.6% vs 7.6%, p < 0.001). No significant differences were observed between groups in EGM duration (39.7 ± 16 ms vs 38.9 ± 12 ms, p = 0.939) or number of deflections (5.9 ± 1 vs 6.0 ± 1, p = 0.805). During a median follow-up of 517[361-800] days, 12 (40%) patients experienced an atrial arrhythmia recurrence, with no difference between groups (HCM: 46.7% vs control: 33.3%, HR=2.6, 95%CI: 0.8 to 8.5, p=0.061).
Conclusion
High-density electroanatomical mapping reveals more extensive intermediate to low-voltage areas and fragmented EGMs in patients with HCM compared with controls, predominantly localized around the left pulmonary veins.