Atrial Fibrillation Recurrence is Higher in Hypertrophic Compared to Other Cardiomyopathies-Insights from LGE-MRI Scans

Yaacoub Chahine, MD – Internal Medicine Resident, University of Washington; hala Al yasiri, MD – Research Assistant, University of Washington; Lee Bockus, MD,PHD – Cardiology Research Fellow, University of Washington; Nazem Akoum, MD – Section head of Cardiac Electrophysiology, University of Washington

Purpose: Atrial fibrillation (AF) is highly prevalent in patients with hypertrophic cardiomyopathy (HCM) as well as other cardiomyopathy (CM) phenotypes. We compared the burden and distribution of left atrial (LA) fibrosis, and recurrence of AF following ablation in patients (pts) with HCM and other CMs.

Material and Methods: Pts were identified from the University of Washington Cardiac Arrhythmia Data Repository (CADRe), and divided into HCM, ischemic CM (ICM), non-ischemic CM (NICM), and no CM. Pre-ablation cardiac magnetic resonance scans were used to evaluate fibrosis using late-gadolinium enhancement (LGE). Pts were followed for arrhythmia recurrence post ablation.

Results: 1461 AF pts were identified, including 47(3.2%) HCM, 243 (16.6%) NICM, 108(7.4%) ICM, and 1062 (72.7%) without CM. HCM pts with AF were younger than their counterparts with a mean age of 63±13 years vs 65±15(No CM), 75±9 (ICM), and 65.4±22 (NICM); p< 0.001. HCM pts also had a higher % of females (36%) compared to ICM (12%) and NICM (27%); p< 0.001. LA fibrosis was highest in the ICM (23.5±9.1%), followed by HCM (20.8±8.6%), NICM (17.6±7.6%), and no CM (16.6±7.6 %) (Panel A). The regional distribution of LA fibrosis demonstrated more septal involvement in HCM compared to the other groups (p < 0.05) (Panel B). AF recurrence post ablation was highest in HCM at 57.1%, in comparison to no CMP (38.3%, p< 0.001), NICM (39.1%, p< 0.001), ICM (44.4%, p< 0.001) (Panel C).

Conclusions: HCM pts with AF presenting for ablation are younger and with more female representation. They have higher arrhythmia recurrence compared to other AF pts with and without CM. LA septal fibrosis is more extensive in HCM compared to other CMs. Further investigation is warranted to delineate the pathophysiology behind septal wall involvement and recurrence of AF in this category.