Acute atrial fibrillation (AAF) in cardiac surgery postoperative period: evaluation of preoperative and peroperative factors associated with its higher incidence

Background

AAF in cardiac surgery postoperative period is implicated in implements in hospital length of stay and costs. Some pre-operative and peroperative factors have been associated to a higher incidence of the arrhythmia. Advanced age, longer surgery time, mitral valve surgery (MVS) and stopping beta-blockade have been described.

Objectives

To evaluate some preoperative and peroperative factors in order to identify those patients with higher probability for cardiac surgery postoperative AAF.

Patients and methods

Three hundred and fifty adult patients consecutively admitted in postoperative period of cardiac surgery were prospectively followed. Clinical and surgical variables were collected and then compared between patients who developed AAF in postoperative period and those who did not. Statistical techniques were: Student t-test and Fischer test.

Results

In the patients submitted to cardiac arterial by-pass surgery (CABS), the mean age in the two groups were significantly different (69.98 ± 9.67 years old in AAF patients and 62.89 ± 10.65 years old in no AAF patients – P < 0.0001). Water retention during surgery was higher in AAF patients (P = 0.05) while water retention on the first postoperative day was also higher in AAF patients but P value was 0.07. Left atrial diameter, body mass index, surgery time, extra corporeal circulation time, aortic clamping time, diagnostic of diabetes and chronic obstructive pulmonary disease, lactate and creatinine levels and PaO₂/FiO₂ ratio were not statistically different in the two groups. Postoperative AAF incidence was higher in MVS when compared to non-MVS (43.4% versus 22.6% with P < 0.01).

Conclusion

Advanced age, water retention and Mitral Valve Surgery were shown to be predictors for AAF in cardiac postoperative period. The other factors analyzed did not influence the incidence of the arrhythmia but further analyses are needed.