Clinical implications
The fibrotic process possibly plays a crucial role in the development and maintenance of AF.8,9 Keeping in mind that only young patients with paroxysmal AF and less dilated atria display better long-term outcomes,3-5 the presence of LA cardiomyopathy with respect to the progression of the disease might have important implications in ablation outcomes. HCM patients undergo catheter ablation late in the course of their disease (median of 5.9 years after the diagnosis of atrial arrhythmias),3 and therefore an extensive structural and electrical remodeling including LA enlargement and fibrosis is possibly present at the time of catheter ablation. The present findings suggest that patients with obstructive HCM exhibit LA cardiomyopathy that affects long-term ablation outcomes. We postulate that catheter ablation should be performed at the early stages of AF (paroxysmal phase) where the development of LA cardiomyopathy is less likely.