Clinical outcomes of atrial tachyarrhythmia hospitalizations with and without prior thoracic irradiation

Introduction Thoracic 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 association with arrhythmia-related hospitalizations. Methods A retrospective cohort study using the National Inpatient Sample (2016–2022) was conducted. Hospitalizations for atrial fibrillation or flutter were identified using ICD-10 codes. Documented prior thoracic irradiation was defined using a history of radiation therapy code in combination with thoracic malignancy codes. Propensity score matching followed by post-matching multivariable regression adjustment was used to evaluate outcomes. The primary endpoint was in-hospital mortality; secondary endpoints included length of stay (LOS) and total costs. Results Among 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). Hospitalizations with documented prior thoracic irradiation 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). Discussion Documented prior thoracic irradiation identified a clinically complex subgroup of atrial fibrillation or flutter hospitalizations with higher in-hospital mortality, slightly longer length of stay, and greater goals-of-care utilization.