(P128) OUTCOMES AND PREVALENCE OF SUBCLINICAL ATRIAL FIBRILLATION IN HEART FAILURE PATIENTS

Background: Subclinical atrial fibrillation (SCAF) refers to short-lasting atrial fibrillation that is usually only detected with long-term heart rhythm monitoring.1 SCAF is very common in older individuals and its clinical significance is incompletely understood.2 We sought to examine the prevalence of SCAF in a cohort of patients free of AF at baseline following hospitalization for heart failure (HF) and determined the association between SCAF and HF hospitalization and other HF-related outcomes.

METHODS AND RESULTS: Patients admitted to hospital with a primary diagnosis of HF exacerbation who were free of AF at baseline were prospectively recruited across 5 sites in Ontario, Canada. All patients underwent 28-day continuous ECG monitoring applied at the time of hospital discharge to determine prevalence of SCAF. The association between SCAF lasting >= 6 minutes in duration and HF exacerbation, mortality, and other adverse outcomes were determined using multivariable adjusted logistic regression models. The study was approved by ethics review boards at all participating sites (NCT03541616).

241 patients were enrolled (mean age 70.9 ±13.3 years, 49.0% female, mean body mass index (BMI) of 31.6 ±10.8 kg/m2). A total of 41.3% had a prior history of HF and mean left ventricular ejection fraction was 42.3 ±17%. Seventeen patients (7.1%) had SCAF during 28-day ECG monitoring. Median SCAF duration was 75.5 minutes. In regression models adjusted for age, sex, BMI, history of coronary artery disease and type of HF, SCAF was not associated with an increased odds of HF hospitalization at 1 year (odds ratio (OR) 2.47 [95% CI 0.49-12.37], p=.27). However, SCAF increased the odds of cardiovascular death (OR 8.69 [95%CI, 1.52-49.86], p=.01525), all-cause death (OR 6.40 [95%CI, 1.14-35.91], p=.03493), and developing clinical AF (OR 15.9 [95%CI 2.6-96], p=.0026).

Conclusion: SCAF was common in patients with HF but no known prior AF in the first month following an HF admission and it increased the odds of developing clinical AF and mortality. An increased risk of HF rehospitalization was not observed.