Abstract Body (Do not enter title and authors here): Background:
Postoperative atrial fibrillation (AF) significantly increases cardiac arrest risk and mortality following coronary artery bypass grafting (CABG). While clinical predictors are established, the independent impact of socioeconomic factors on outcomes remains poorly characterized. This study aims to evaluate associations between key socioeconomic determinants and adverse outcomes across a 5 year span in CABG patients with postoperative AF.

Methods:
We analyzed National Inpatient Sample(NIS) data (2018-2022) from adults developing AF post-CABG. Van Walraven Weighted Elixhauser Comorbidity index was used to survey logistic and linear regression models (accounting for 38 standardized covariates) assessed associations between specific demographic/socioeconomic factors (sex; race; payer [Medicare, Medicaid, private insurance]) and outcomes: inpatient mortality, length of stay (LOS), and total charges.

Results:
Among 943,570 CABG patients, 32% had Afib and significant disparities emerged. Mortality odds were significantly higher for females (OR 1.70, 95% CI 1.58-1.81, p<0.001), but decreased with private insurance (vs Medicaid: OR 0.75, 95% CI 0.86-0.82, p<0.001) and hispanic patients (vs White: OR 0.86, 95% CI 0.76-0.97, p=0.008). LOS increased for females (β 1.11 days, 95% CI 1.02-1.20, p<0.001), Black (vs White: β 1.22, 95% CI 1.05-1.39, p<0.001), Hispanic (vs White: β 0.65, 95% CI 0.49-0.80, p<0.001), and Asian patients (vs White: β 0.28, 95% CI 0.06-0.50, p=0.014), and Medicare recipients (vs Medicaid: β 1.30, 95% CI 1.11-1.49, p<0.001). Private insurance reduced LOS (vs Medicaid: β -0.27, 95% CI -0.37 to -0.17, p<0.001). Total charges were higher for racial minorities (vs White: Black β $20,635, Hispanic β $52,702, Asian β $34,962; all p<0.001) and Medicare patients (vs Medicaid: β $10,310, 95% CI $4,560-$16,060, p<0.001), but lower with private insurance (vs Medicaid: β -$9,636, 95% CI -$12,868 to -$6,403, p<0.001).

Conclusion:
Significant socioeconomic disparities exist in post-CABG AF outcomes, with females, racial minorities, and Medicaid/Medicare patients experiencing worse outcomes across mortality, LOS, and cost metrics. These findings highlight the urgent need for equity-focused interventions in cardiac surgical care.