Abstract 15364: The Association of Exhaled Carbon Monoxide With Atrial Fibrillation and Left Atrial Size in the Framingham Heart Study

Background: Studies from the Framingham Heart Study (FHS) have reported that exhaled carbon monoxide (eCO) is associated with cardiovascular disease (CVD) and stroke. To our knowledge, no study has assessed the association between eCO with atrial fibrillation (AF) and left atrial (LA) size. We related eCO to AF and LA size. Methods: eCO was measured using an Ecolyzer instrument among participants who attended Exam 6 and Omni 1 participants who attended Exam 1. AF was assessed on electrocardiography (ECG) and LA size on echocardiography. We used Cox and logistic regression models in assessing the relationship between eCO and incident AF (primary model), and prevalent AF and LA size (secondary models). Participants were also analyzed according to tertiles of eCO concentration, and we also adjusted for current smoking, and other covariates - age, race, sex, height, weight, systolic blood pressure (BP), diastolic BP, diabetes, hypertension treatment, prevalent myocardial infarction (MI), and prevalent heart failure (HF). Results: Our study sample included 3814 participants, with a median age of 58 ± 10 years; 54.4% were women, and 11.6% of the study population was non-White. eCO was associated with incident AF after adjusting for known AF risk factors (HR=1.31, 95% confidence interval [CI] 1.09-1.58). Higher eCO levels were associated with an increased cumulative risk of AF, with the risk rising with increasing tertiles of eCO. The association remained significant after additionally adjusted for CRP and BNP, and interim MI and HF. In the stratified analysis, eCO remained associated with incident AF in the men-only analysis and in never or previous smokers (men: HR: 1.30, CI: 1.02-1.65, p = 0.03; never or previous smokers: HR: 1.39, CI: 1.31-1.72, p = 0.002), but not in women, current smokers and age-stratified (≤60 years and >60 years) analyses. eCO was not associated with LA size or prevalent AF in either age and sex adjusted models or multivariable adjusted models. Conclusion: We found an association between eCO and incident AF after adjusting for known AF-related risk factors. There is a need for more research to better understand how eCO mediates incident AF, how much it may contribute to the pathogenesis of AF, and potential therapeutic benefits it may offer.