Risk factors, morbidity, and mortality associated with atrial fibrillation in the postoperative period of cardiac surgery.

OBJECTIVE

To determine the incidence of atrial fibrillation in the postoperative period of cardiac surgery, its impact on morbidity, mortality, and hospital stay, and to analyze the risk factors in the pre, trans, and postoperative periods.

METHOD

Contemporary cohort study with 158 adult patients undergoing cardiac surgery, of whom those with atrial fibrillation in the preoperative period were excluded. The patients were assessed with continuous cardiac monitoring and daily electrocardiograms. Any episode of irregular rhythm with the presence of f waves of variable morphology and amplitude was considered atrial fibrillation.

RESULTS

The general incidence of atrial fibrillation was 28.5%, being 21.6% for revascularized patients and 44.3% for those undergoing valvular repair. Factors independently associated with atrial fibrillation were left heart failure in the preoperative period (p=0.05; RC=2.2), total fluid balance (p=0.01; RC=1.0), duration of surgery (p=0.03; RC=1.01) [and other associated factors, age > 70 years, aortic valvular disease, psychomotor agitation, length of installation of the drains, pulmonary congestion and respiratory insufficiency in the postoperative period]. The use of beta-blockers (p=0.01; RC=0.3) was a protective factor. Atrial fibrillation in the postoperative period was associated with an increase in the length of hospital stay (16.9+/-12.3 days versus 9.2+/-4.0 days, p<0.001) and a greater incidence of stroke or postoperative death (p=0.02).

CONCLUSION

The incidence of atrial fibrillation in the postoperative period of cardiac surgery was high and caused a significant increase in morbidity, mortality, and the length of hospital stay. Among the independent risk factors, excessive fluid balance is significant. The use of beta-blockers was identified as a protective factor.