Traumatic brain injury is associated with the subsequent risk of atrial fibrillation or atrial flutter

Background: Traumatic brain injury (TBI) is associated with a variety of adverse long-term outcomes and increases sympathetic nervous system activation, which could increase the risk of arrhythmias including atrial fibrillation or atrial flutter (AF/AFL). Objective: We examined episodes of TBI and subsequent AF/AFL in a large cohort of post-9/11 servicemembers and veterans. Methods: The variable of interest was TBI, stratified by severity (mild, moderate/severe, and penetrating). The outcome was a subsequent diagnosis of AF/AFL. We used Fine-Gray competing risks models to evaluate the potential risk imparted by TBI on subsequent AF/AFL. Results: Of the 1,924,900 participants included in the analysis, 369,891 (19.2%) experienced an episode of documented TBI. Most were young (63% <35 years), male (81.7%), and non-Hispanic White (62.7%). AF/AFL was diagnosed in 22,087 patients. On univariate analysis, only penetrating TBI (hazard ratio [HR], 2.02; 95% confidence interval [CI], 1.84–2.23; P <.001) was associated with AF/AFL compared with veterans without TBI. After adjustment in the full multivariable model (adjusted for age, sex, race and ethnicity, service branch, rank, component, and comorbidities), mild (HR 1.27, 95% CI 1.22–1.32; P <.001), moderate/severe (HR, 1.34; 95% CI, 1.24–1.44; P <.001), and penetrating TBI (HR, 1.82; 95% CI, 1.65–2.02; P <.001) were significantly associated with AF/AFL compared with no TBI. Post hoc analyses demonstrated that the risk of AF/AFL was concentrated in female and younger patients. Conclusion: We found that an episode of TBI, particularly penetrating TBI, significantly increased the risk for AF/AFL. Further work is needed to delineate the long-term risk of arrhythmias after TBI.