Abstract 12930: Atrial Myopathy and the Risk of Incident Atrial Fibrillation in People With Newly Diagnosed Cavotricuspid Isthmus-Dependent Atrial Flutter

Abstract

Background New cavotricuspid isthmus-dependent atrial flutter (AFL) is associated with increased risk of incident atrial fibrillation (AF). It is unclear which patients with AFL will develop AF. Hypothesis: Patients with new AFL who have co-existing atrial myopathy, detected by measuring left atrial emptying fraction (LAEF) and left atrial reservoir strain (LARS), may be at increased risk for developing AF. Methods: There were 210 patients who received an ablation or cardioversion for AFL at a tertiary care medical center between 2015-2022. Patients were excluded for prior AF (118), congenital heart disease (16), valve surgery and heart transplant (9), no echocardiogram available (9), and less than 6 months of follow up (9). Data was obtained by retrospective chart review. Covariates included coronary heart disease, heart failure, diabetes, age, sex, vascular disease, and stroke. Exposure variables included LAEF and LARS. We used Cox proportional hazards models to estimate the risk of AF for LAEF and LARS. Results: 49 patients (mean age 62.3 years, 18.3% female) met criteria for inclusion, and 18 developed atrial fibrillation over a mean follow up period of 29.9 months (19.7 months). Those who developed AF had lower LAEF and LARS compared to those who did not. For every 5% decrease in LAEF and LARS, there was a 1.79 (1.33, 2.38) and 5.26 (1.75, 16.67)-fold increase in risk of AF after adjustment for covariates. Conclusion: Co-existing atrial myopathy, measured by decreased LAEF and LARS, is associated with increased risk of AF in people with new AFL.