Introduction
Atrial fibrillation (AF) is commonly seen in patients with hypertrophic
cardiomyopathy (HCM) (~20%).1Catheter ablation (CA) is a reasonable therapeutic approach in selected
patients with HCM and AF (class IIa indication, Level of Evidence
B).2 Studies addressing the efficacy of AF CA in
patients with HCM are limited and have demonstrated worst long-term
outcomes compared to non-HCM patients.3-7 Persistent
AF, female gender, age, New York Heart Association (NYHA) functional
class, LA enlargement, and left ventricle (LV) outflow tract obstruction
have been proposed as predictors of AF recurrence following catheter
ablation in this specific population.3-5 Pulmonary
vein (PV) isolation only appears insufficient to improve the long-term
arrhythmia survival in HCM patients, possibly due to extensive LA
remodeling.6
Among AF patients undergoing catheter ablation, atrial tissue fibrosis
assessed by delayed enhancement magnetic resonance imaging was
independently associated with arrhythmia recurrence.8The presence of LA cardiomyopathy estimated by high-density
electroanatomical mapping (EAM) has been associated with AF relapse
following catheter ablation.9,10 Data regarding the
EAM LA substrate in patients with HCM and AF are missing. In this
high-density EAM study, we evaluated for the first time the extent of LA
fibrosis and its impact on catheter ablation outcomes in patients with
HCM and AF.