Relationship between perioperative left atrial appendage doppler velocity estimates and new-onset atrial fibrillation in patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass.

Background: Literature search reveals that postoperative atrial fibrillation (POAF) occurs in 15%-40% of coronary artery bypass graft (CABG) patients. Although several risk models exist for predicting the development of POAF, few have studied left atrial appendage (LAA) velocity. We hypothesize that an association between LAA velocity and development of POAF exists.
Design and Methods: Single institution university hospital prospective observational clinical study performed between May 2016 and November 2016 in 96 adult patients undergoing CABG surgery utilizing cardiopulmonary bypass (CPB). Transesophageal echocardiography was performed perioperatively to measure LAA velocity and left atrial (LA) size after anesthetic induction, post-CPB and during the postoperative period before extubation. Student's t-test was used for inter-group comparisons. Data are expressed as mean ± (standard deviation). The value of P < 0.05 was considered statistically significant.
Results: A total of 95 patients (69 males and 26 females) completed the study and were included in the final analysis. Of these, 21 (22%) (15 males and 5 females) developed POAF. The patient group which developed POAF was compared with the group that did not develop POAF. On comparing mean age of patients in each group (59 years in patients with no POAF and 63.71 years in patients with POAF, P = 0.04). LA volume indexed in POAF group (34.13 ml/m2) compared with that in group with no POAF (34.82 ml/m2) resulted in P = 0.04. Mean LAA velocities (pre-CPB, post-CPB, postoperative Intensive Care Unit) in group with no POAF were 41.06, 56.33, and 60.44 cm/s, respectively, whereas in the other group with POAF the values were 39.68, 55.04, and 58.09 cm/s, respectively. No statistical significance was noted (P > 0.05). Comparison of comorbidities also did not yield any significant results (P > 0.05).
Conclusions: Decreasing LAA velocity does not appear to independently predict the development of POAF in patients undergoing CABG surgery with the use of CPB. There is, however, a positive correlation of POAF with age and LA volume.