Risk of Atrial Fibrillation Increased in HFpEF

Congestive heart failure (with decreased ejection fraction) has always been recognized as a risk factor for stroke or systemic embolism in patients with atrial fibrillation (AF) and is included in the CHA₂DS-VASc risk score calculation. It has only been recognized recently, however, that heart failure with preserved ejection fraction (HFpEF) may also be a marker of risk.

In a study presented at the Heart Failure Society of America meeting in September 2015 in Maryland, Cogswell and colleagues presented data from the Atherosclerosis Risk In Communities (ARIC) cohort that demonstrated a very high rate of subclinical infarcts in individuals with HFpEF but no known AF. In this observational analysis of 1527 patients from ARIC, the individuals were divided into 4 groups based on the presence or absence of AF and presence or absence of HFpEF and followed up with MRI scans.  Not surprisingly, the lowest rate (~17.3%) of subclinical infarcts was in patients with neither HFpEF nor AF. However, it was surprising to see that the group with highest rate (29.3%) of subclinical infarcts was the group with HFpEF but no known AF. This rate of events was even higher than those with known AF but no HFpEF (24.5%) and those with both HFpEF and AF (23.5%). Adjustments were made for important confounding factors, such as warfarin use, age, race, sex, BMI, hypertension, diabetes, coronary artery disease, and location of enrollment. 

The clinical significance of these incidentally detected infarcts in HFpEF remains uncertain but suggests that occult AF may underlie these MRI findings. However, although those with subclinical infarcts had lower scores on cognitive function tests including the Mini-Mental Status Examination, the cognitive defects did not appear to track with HFpEF the way that they tracked with AF. This suggests that the source of the deficits (and their associated subclinical infarcts) in HFpEF may be a cause other than AF. Additional larger prospective data is needed to determine whether this association is reproducible and whether AF may be the causal link. In the meantime, however, as clinicians, we may consider screening our HFpEF patients a little more rigorously for occult AF and start treating HFpEF as a marker of risk.

References:

Cogswell RJ, Norby FL, Gottesman RF, et al. High prevalence of subclinical cerebral infarctions in patients with heart failure with preserved ejection fraction. J Card Fail 2015;21:S104–S105. Abstract 242.