Autonomic changes preceding the onset of postoperative atrial fibrillation

Background: The mechanisms of atrial fibrillation/flutter (AF) after major thoracic surgery remain controversial. The goal of the present study was to evaluate autonomic changes preceding postoperative AF. Methods: In 48 patients with postoperative AF 2 h Halter recordings prior to the onset of AF were compared wth corresponding data from 48 ageand gender-matched surgical controls without AF. Five-minute segments of heart rate variability were studied using reoeated measwes ANOVA. Results: There was a near significant trend for the RR-interval among AF patients to be lower than controls IP=O.OE& while the standard deviation of RRs fP