Overweight and Aging Increase the Risk of Atrial Fibrillation After Cardiac Surgery Independently of Left Atrial Size and Left Ventricular Ejection Fraction

Abstract Background: Body mass index (BMI), age, left atrium (LA) dimensions and left ventricular ejection fraction (LVEF) have been linked to post-operative atrial fibrillation (POAF) after cardiac surgery. The aim was to better define the role of these risk factors. Methods: This study evaluated 249 patients (without prior atrial dysrhythmia) undergoing cardiac or aortic surgery . Prior to surgery the following data were collected: age (yrs), BMI (kg/m2), LA diameter (cm), LA area (cm2), LVEF (%), the presence of arterial hypertension (AH) and of diabetes, tyroid stimulating hormone (TSH, mU/L) and, creatinine (mg/dL). Results: Patients with (n. 127, 51%) and without POAF (n. 122, 49%) were compared. No difference was observed for sex, LA diameter, LA area, LVEF, TSH and diabetes. Instead, patients with PoAF had higher values of age, BMI, creatinine and a greater prevalence of AH and Bentall procedures. Multivariable analysis showed that the only independent predictors of PoAF were: age (OR = 1,05, CI 95% 1,025-1,076, p= 0,0001) and BMI (OR=1,095, CI 95% 1,015-1,182, p= 0,019). Conclusions: Results suggest that advanced age and a higher value of BMI are strong risk factors for POAF in patients without previous AF. This even in the presence of comparable LA dimensions and LVEF.