Atrial Fibrillation Begets Heart Failure and Vice Versa: Temporal Associations and Differences in Preserved vs. Reduced Ejection Fraction

Background —Atrial fibrillation (AF) and heart failure (HF) frequently coexist and together confer an adverse prognosis. The association of AF with HF subtypes has not been well-described. We sought to examine differences in the temporal association of AF and HF with preserved versus reduced ejection fraction (HFpEF vs HFrEF). Methods and Results —We studied Framingham Heart Study participants with new-onset AF and/or HF between 1980-2012. Among 1737 individuals with new AF, (mean-age 75±12, 48% women) more than one third (37%) had HF. Conversely among 1166 individuals with new HF (mean-age 79±11, 53% women), more than half (57%) had AF. Prevalent AF was more strongly associated with incident HFpEF (multivariable-adjusted hazard ratio [HR] 2.34, 95% confidence interval [CI] 1.48-3.70, no AF as referent) vs HFrEF (HR 1.32, 95%CI 0.83-2.10), with a trend toward difference between HF subtypes (P for difference 0.06). Prevalent HF was associated with incident AF (HR 2.18, 95%CI 1.26-3.76, no HF as referent). The presence of both AF and HF portended greater mortality risk compared with those without either condition, particularly among individuals with new HFrEF and prevalent AF (HR 2.72, 95%CI 2.12-3.48) compared with new HFpEF and prevalent AF (HR 1.83, 95%CI 1.41-2.37, P for difference 0.02). Conclusions —AF occurs in more than half of individuals with HF, and HF in more than one third of individuals with AF. AF precedes and follows both HFpEF and HFrEF, with some differences in temporal association and prognosis. Future studies focused on underlying mechanisms of these dual conditions are warranted.