Abstract 4135905: The Impact of Emergent Atrial Fibrillation in Patients With Newly Diagnosed Heart Failure and Differences in Risk Among Preserved vs. Reduced Ejection Fraction

Background: Atrial fibrillation (AF) and heart failure (HF) are associated with an increased risk of adverse events, with their diagnoses often coexisting. The impact of AF in HF needs additional study, with further delineation among HF type. Therefore, this study sought to determine the degree of AF burden among newly diagnosed HF patients and whether differences in risk exist between heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF) patients. Methods: Patients with new-onset HF between 2000-2019 were studied. To be included, patients had to have 1-year of follow-up, an ejection fraction (EF) measurement within 30 days of HF diagnosis, and no history of cancer. EF was used to define HFrEF (EF <40%) and HFpEF (EF > 40%). Multivariable Cox hazard regression was used to evaluate the risk of death and HF hospitalization at 1- and 3-years. Results: A total of 21,925 patients were studied with HFrEF (n=7931 [36.2%]) and HFpEF (n=13,994 [63.8%]). HFpEF patients were older (74 vs. 65 years) and more often female (53.7% vs. 33.1%). Prevalent AF was 40.5% (n=8879), being more common in HFpEF compared to HFrEF (65.2% vs. 34.8%). Among AF patients, HFpEF patients were also older (76 vs. 72 years) and more often female (52.7% vs. 30.8%) compared to HFrEF. The presence of AF was associated with an increased risk of HFpEF (OR=1.11, p=0.001). Prevalent AF was associated with an increased risk of death and follow-up HF hospitalization (Table). Death at 1-year and 3-years were similar between the HF groups (Table). However, the risk of HF hospitalization was greater among HFrEF patients (Table). Similar associations persisted when AF patients were propensity matched (Table). Conclusions: Among a newly diagnosed HF population, AF was common (40%) and was associated with an increased risk of HFpEF, death, and HF hospitalization. These results provide a rationale for aggressive management of HF and AF patients and the need for a randomized clinical trial to determine optimal therapy by ablation and 4-pillar HF therapy.