LOW VAGAL TONE AND SUPRAVENTRICULAR ECTOPIC ACTIVITY PREDICT ATRIAL-FIBRILLATION AND FLUTTER AFTER CORONARY-ARTERY BYPASS-GRAFTING

To investigate the impact of pre-operative autonomic balance and atrial ectopic activity on the risk of atrial fibrillation or flatter after aorto-coronary artery bypass surgery 24-h Holter monitoring was analysed in 102 patients before coronary artery bypass grafting. Index for vagal tone was calculated as % successive RR interval differences >6%. Twenty-nine (28%) of the 102 patients developed atrial fibrillation or flutter. Independent predictors (90% confidence interval) of postoperative atrial fibrillation or flutter were identified by logistic regression analysis: the independent predictors were older age, relative risk 1.07. year(-1) (1.02-1.12), vagal index <10% relative risk 4.50 (1.40-14.5), greater than or equal to 10 ectopic supraventricular beats. 24 h(-1), relative risk 3.03 (1.05-8.72), and one or more events of non-sustained supraventricular tachycardia, relative risk 3.02 (1.11-8.22). Thus, age of the patient, attenuated pre-operative cardiac vagal modulation, ectopic supraventricular,. beats, and paroxysmal non-sustained supraventricular tachycardia are independent risk factors for the development of atrial fibrillation or flutter after coronary artery bypass surgery.