ROLE OF ATRIAL ISCHEMIA IN DEVELOPMENT OF ATRIAL-FIBRILLATION FOLLOWING CORONARY-ARTERY BYPASS-SURGERY

Objective: Atrial fibrillation (AF) is a common complication after cor onary artery bypass grafting (CABG) operations, occurring in 5 to 40% of cases. A number of studies have implicated atrial ischaemia in the genesis of this arrhythmia. The aim of this study was to examine the r elationship between atrial coronary anatomy and the incidence of post operative atrial fibrillation. Method: To investigate a possible anato mical explanation to the onset of AF after CABG, 25 patients with docu mented AF after CABG were matched and compared to 25 patients which re mained in sinus rhythm (SR). All coronary angiograms were reported bli ndly by a cardiac radiologist with reference to the blood supply of th e sino-atrial (SA) node and atrio-ventricular (AV) node before and aft er surgery. Results: Univariate analysis of risk factors did not ident ify any significant difference (Fisher exact test, P > 0.05) between t he two groups in age, gender, left ventricular function, ischaemic tim e, number of vessels diseased or grafted, renal dysfunction and withdr awal of beta-blockade. However, significant disease in the SA nodal ar tery was present in 2 patients of the SR group when compared to 9 in t he AF group. Significant disease of AV nodal artery was present in onl y 4 patients of the SR group when compared to 18 in the AF group. Comp arison between the two groups showed a significantly increased inciden ce of SA or AV nodal artery disease in the AF group, (SA: P = 0.018, A V: P = 0.0001). Mean hospital stay was 8.1 days for the SR group and 9 .1 days in the AF group (P = 0.175). Conclusion: Obstructive disease i n the SA nodal and AV nodal arteries is more common in patients develo ping atrial fibrillation following coronary artery bypass surgery than those who remain in sinus rhythm. If the incidence of AF could be pre dicted by the anatomical distribution of arterial disease then targeti ng prophylaxis to this group may be possible. Copyright (C) 1997 Elsev ier Science B.V.