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Prevalence of Subclinical Atrial Fibrillation in HFpEF
Quick Takes
- In a cross-sectional study of HFpEF patients, subclinical AF was more common on continuous ambulatory ECG monitoring compared to patients without HFpEF.
- Subclinical AF correlated with more dyspnea in HFpEF patients than in those without HFpEF.
- Subclinical AF correlated with shorter 6MWT distances in HFpEF patients than in those without HFpEF.
Study Questions:
What is the prevalence of subclinical atrial fibrillation (AF) in patients with heart failure and preserved ejection fraction (HFpEF), and how does it impact outcomes?
Methods:
This was a cross-sectional study of patients with HFpEF in two health care systems. Control subjects were drawn from the MESA (Multi-Ethnic Study of Atherosclerosis) cohort. Subclinical AF (i.e., AF lasting >30 seconds) was detected using a continuous ambulatory electrocardiographic (ECG) monitor for up to 14 days. Amyloidosis was excluded. Outcomes included 6-minute walk test (6MWT) and dyspnea with activity.
Results:
This study included 101 patients with HFpEF and 1,557 MESA participants with continuous ECG monitor including 90 with HFpEF and 1,230 without HF. Patients with HFpEF were younger (mean age 65 vs. 72 years), more obese, and more likely to be Black with significantly higher burden of hypertension, diabetes, and dyslipidemia with lower 6MWT distance.
Subclinical AF was more common with HFpEF (9% vs. 4%) and this persisted after multivariable adjustment (odds ratio, 3; 95% confidence interval, 1.1-8.0). Prevalence of subclinical AF did not increase with age in HFpEF in contrast to participants without HFpEF. However, time in AF did not correlate with presence of HFpEF. Presence of AF correlated with exertional intolerance in HFpEF with shorter 6MWT distances. In contrast, subclinical AF in non-HFpEF patients did not correlate with symptoms or 6MWT distance. Subclinical AF in HFpEF did not correlate with other arrhythmias.
Conclusions:
In a cross-sectional study of HFpEF patients, subclinical AF was more common on continuous ambulatory ECG monitoring compared to patients without HFpEF. Subclinical AF correlated with more symptoms in HFpEF patients than without, with shorter 6MWT distances.
Perspective:
AF is a well-established risk factor for worse outcomes in HFpEF patients. However, with an increase in use of wearables and ambulatory ECG monitoring, diagnosis of subclinical AF is increasing. This study demonstrates that subclinical AF in HFpEF patients is more common and correlates with more symptoms and disability, suggesting that it could serve as a prognostic marker. Important strengths include use of a well characterized HFpEF and control cohort with data on ambulatory ECG monitoring available. However, whether treating subclinical AF leads to clinical improvement or mitigates thromboembolic risk remains to be established.
Clinical Topics: Arrhythmias and Clinical EP, Atrial Fibrillation/Supraventricular Arrhythmias, Heart Failure and Cardiomyopathies
Keywords: Atrial Fibrillation, Heart Failure, Preserved Ejection Fraction
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