PO-05-169 VENTRICULAR SCAR BY CARDIAC MRI IS A PREDICTOR OF ATRIAL FIBRILLATION IN HYPERTROPHIC CARDIOMYOPATHY

Abstract

Atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) increases risk of stroke and mortality. The reported prevalence of AF in HCM ranges from 18% to 28%, which is higher than the general population; even after accounting for traditional risk factors including obesity, hypertension, and age. Several factors increase risk of AF in HCM including left atrial size and the presence of ventricular obstruction. However, there is paucity of data correlating ventricular late gadolinium enhancement (LGE) to the incidence of AF in HCM. Our study aims to investigate whether left ventricular LGE can predict the rate of AF in patients with HCM We identified all patients who were at least 18 years of age with HCM who underwent a cardiac MRI from May 2014 to March 2022. Patients’ baseline characteristics were compared between those who did and did not develop atrial fibrillation. Using a two-sample t-test, we compared the incidence of AF in the two groups. The rate of AF was further broken down with relation to left ventricular LGE and split into four categories: 0%, 1-5%, 6-14%, and ≥15%. A t-test or ANOVA (or their variance) were used for the continuous characteristics to compare the two groups and a Chi-square test was used for the categorical characteristics. A p-value of <0.05 was deemed as significant. Baseline characteristics were collected in 351 patients. Total AF prevalence was 39.6%. The rate of AF was 27.6% with 0% LGE, 38.5% with 1-5% LGE (p-value 0.101), 44.4% with 6-14% LGE (p-value 0.043), and 54.7% with ≥15% LGE (p-value 0.002). Furthermore, independent of age, percent LGE predicted AF especially at ≥15% (p-value 0.001). Our study suggests that left ventricular LGE independently predicts the incidence of AF in patients with HCM. The strongest correlation was identified at LGE ≥15% with 54.7% of this cohort developing AF. This has important implications regarding empiric anticoagulation in this group of patients with ≥15% LGE before they develop AF, especially since the CHADSVASc score has not been validated in HCM patients. Future studies are needed to assess if different anticoagulation strategies based on LGE percent have potential benefits in this patient population.