(P131) PREDICTORS OF EARLY RHYTHM CONTROL AND ASSOCIATED CARDIOVASCULAR OUTCOMES IN PATIENTS WITH ATRIAL FIBRILLATION: A POPULATION BASED ANALYSIS

Background: Recent guidelines for the management of atrial fibrillation (AF) have highlighted the role for early rhythm control (within 1 year of diagnosis) to delay disease progression and risk of adverse cardiovascular outcomes. The study objectives were: (a) to describe real-world practice patterns of rhythm and rate control within the first year of AF diagnosis, (b) to identify predictors of early rhythm control, and (c) to assess cardiovascular outcomes in early rhythm control versus rate control groups.

METHODS AND RESULTS: Using linked administrative data from Alberta, Canada (2008-2020), adults (≥18 years) with a new diagnosis of AF were included and classified based on their arrhythmia management strategy within the 1 year: (a) rhythm control (i.e., class I and III antiarrhythmic drugs, cardioversion, or catheter ablation), (b) rate control alone, or (c) no rate or rhythm control. Predictors of early rhythm control were identified using multilevel regression models to account for clustering of physician prescribing practices. Cox proportional hazard models were used to compare cardiovascular outcomes in a propensity score matched early rhythm cohort and rate control cohort.

Of 99,146 patients with a new diagnosis of AF (mean age 65.9 years, 43.6% female, mean CHADS2VASc score 3.1), 13.0% (n=12,908) were managed with rhythm control, 49.9% (n=49,477) with rate control alone, and 37.1% (n=36,761) with no rhythm or rate control therapies. An early rhythm control strategy was more likely selected in patients with heart failure, valvular heart disease, those assessed by a cardiologist, or if AF was diagnosed in the emergency department or inpatient setting. Negative predictors included female sex and increasing age (Figure 1). In the propensity score matched cohort, early rhythm control was associated with a lower risk of ischemic stroke/TIA (HR 0.83, 95%CI 0.74-0.93) and all-cause mortality (HR 0.91; 95%CI 0.85-0.97) compared to rate control at 5 years. However, early rhythm control was associated with an increased risk of all-cause hospitalization (HR 1.13; 95%CI 1.05-1.22).

Conclusion: Early rhythm control is an infrequent arrhythmia management strategy within the first year of AF diagnosis. While patient factors influence selection of early rhythm control, physician and geographic factors are important determinants of strategy including physician specialty and location of diagnosis. Fewer females received early rhythm control, suggesting possible sex-based bias in treatment patterns. Improved survival and lower risk of stroke observed among patients with access to early rhythm control suggests a closer examination of the processes in determining an initial AF management strategy.