Autonomics, More Than Fibrosis, Predict Postoperative Atrial Fibrillation

A study examined the causes of postoperative atrial fibrillation (POAF) occurring after heart surgery in 6,697 patients without prior atrial fibrillation. Researchers tested the hypothesis that POAF is primarily caused by fibrosis in the atria. They found that fibroblast activation in the atria did not significantly differ between patients with and without POAF. Conversely, heart rate variability analysis revealed progressive destabilization of the autonomic nervous system approximately 20 minutes before POAF onset. In the final 10 minutes before arrhythmia, a significant change in the measured SDNN parameter was recorded (P<0.001). These findings were confirmed in an independent patient cohort with sensitivity of 69.6% and specificity of 97.5%. The results suggest that POAF is caused more by dynamic destabilization of the autonomic nervous system rather than structural changes in the heart.