Atrial Pacing May Decrease the Incidence of Atrial Fibrillation Following Coronary Artery Bypass Graft Surgery

Abstract

At the Montreal General Hospital in 1994, the incidence of atrial fibrillation (AF) following coronaryartery bypass graft (CABG) surgery was 30%. With the goal of reducing the incidence of thiscomplication, 20 patients (15 males and 5 females) undergoing CABG surgery were studied
 prospectively for the occurrence of AF following a three-day "on demand" atrial pacing at 90 beats-per-minute. The age range of the group was 39 to 79 years, with a mean age of 60 and a median age of
 63. Two patients were categorized in NYHA class II, 13 in class III, and five in class IV. Of the latter
 five, two patients received intravenous nitroglycerin preoperatively. ß-blockers were taken pre-operatively by 13 patients, Ca2+ channel blockers by 12, and ACE inhibitors by two. Only one patient
 had suffered a myocardial infarction within the last year. Preoperative ejection fractions ranged from15 to 60% with a mean of 45%. In all cases, the CABG operation achieved complete revascularizationusing left internal mammary artery (LIMA) grafts in addition to saphenous vein grafts. The averagenumber of bypasses performed was 3.15. Cardiac arrest was induced using intermittent cold bloodcardioplegia, and cardiopulmonary bypass time averaged 60 minutes. Aortic occlusion time averaged36 minutes. Intraoperative inotrope use was infrequent, used intraoperatively with two cases requiringneosynephrine, one case requiring levophed, and one case requiring dobutamine. Post-pacing cardiacassessment revealed non-specific T wave abnormalities in five (25%) of patients, but no patient showedany evidence of acute myocardial infarction. In no cases did any complications related to the atrialpacing develop in the postoperative period. The results reveal that only two patients (15%) experiencedAF following, and one during, the three-day regimen of atrial pacing. Thus, this study providespreliminary evidence of a decrease in the incidence of post-CABG AF using atrial pacing.