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: To examine 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/AL.

Results: Among the 1,924,900 subjects included in the analysis, 369,891 (19.2%) experienced an episode of documented TBI. Most were young (63% less than 35 years), male (81.7%) and non-Hispanic White (62.7%). AF/AFL was diagnosed in 22,087 subjects. On univariate analysis, only penetrating TBI (hazard ratio [HR] 2.02, 95% confidence interval [CI] 1.84-2.23; p<0.001) was associated with AF/AFL compared to 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<0.001), moderate/severe (HR 1.34, 95% CI 1.24-1.44; p<0.001), and penetrating TBI (HR 1.82, 95% CI 1.65-2.02; p<0.001) were significantly associated with AF/AFL compared to 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.