[Causes of atrial fibrillation early after coronary artery bypass grafting]

The aim of the study was to define the frequency of atrial fibrillation early after coronary artery bypass grafting (CABG) and clinical risk factors for the development of atrial fibrillation in the post-operative course. The study population consisted of 1578 patients (1283 men and 295 women ranging in age from 25 to 85 years, mean age 59.373 +/- 8.686 years) undergoing isolated coronary artery bypass grafting in extracorporeal circulation between 1.01.1998 and 21.12.1999. The patients were divided into two groups: group 1 with atrial fibrillation after CABG (193 patients, mean age 62.399 +/- 7.097 years) and group 2 without atrial fibrillation in the postoperative course (1385 patients, mean age 58.952 +/- 9.009 years). Both groups were compared with respect to pre-, intra- and postoperative parameters. Additionally in group 1 the following aspects were taken into account: timing of atrial fibrillation and its relapses in relation to the surgical procedure, serum potassium level, type and efficacy of antiarrhythmic treatment.

Postoperative atrial fibrillation developed in 193 patients i.e. 12.23% of the CABG population. The complication occurred most frequently on the third day after the procedure and it recurred in about 60% of the patients. Analysis of clinical pre, intra- and postoperative factors identified those affecting the occurrence of atrial fibrillation in the postoperative course as follows: age, paroxysmal atrial fibrillation occurring before the operation, previous inferior myocardial infarction, type 2 diabetes mellitus, arterial hypertension, left ventricular ejection fraction, left atrial size, volume of cardioplegia used during the procedure, volume of blood lost during the procedure, postoperative ischaemia, timing of postoperative ischaemia, perioperative withdrawal of beta adrenolytics, prolonged intubation after the procedure, low cardiac output syndrome, prolonged administration of pressor amines after CABG, and Intraaortic balloon counterpulsation, especially during the procedure.

(1) Atrial fibrillation is an important clinical problem early after coronary artery bypass grafting. It is poorly tolerated and shows a tendency to recur. (2) Atrial fibrillation after CABG is most strongly correlated with age over 60 years, arterial hypertension and perioperative withdrawal of beta adrenolytics.