Clinical Outcomes in Hospitalized Atrial Tachyarrhythmia Patients With and Without Prior Thoracic Irradiation

BackgroundThoracic radiation therapy (TRT) is commonly used for breast, lung, and lymphoid cancers. While its cardiotoxic effects, particularly coronary artery disease, are well recognized, less is known about its impact on arrhythmia-related hospitalizations. MethodsA retrospective cohort study using the National Inpatient Sample (2016-2022) was conducted. Admissions for atrial fibrillation or flutter were identified using ICD-10 codes, and prior TRT was determined from thoracic malignancy and radiation history codes. Propensity score matching and doubly robust multivariable regression were used to evaluate outcomes. The primary endpoint was in-hospital mortality; secondary endpoints included length of stay (LOS) and total charges. ResultsAmong 3,198,304 weighted admissions, 8,570 (0.27%) had prior TRT. After matching, TRT was associated with higher odds of in-hospital mortality (adjusted odds ratio [aOR] 1.97; 95% CI 1.17- 3.32; p=0.010) and longer LOS (+0.30 days; 95% CI 0.05-0.55; p=0.019) without increased costs (p=0.202). TRT patients also had higher odds of palliative consultation (aOR 2.60, p<0.001) and DNR status (aOR 1.97, p<0.001), but lower odds of acute kidney injury (aOR 0.66, p<0.001). ConclusionPrior TRT is linked to greater in-hospital mortality and resource utilization during atrial fibrillation or flutter admissions, likely reflecting cumulative cardiovascular injury. These findings support closer surveillance and early intervention for this high-risk population.