The impact of volume substitution on post-operative atrial fibrillation

Post-operative atrial fibrillation (POAF) represents a common complication after cardiac valve or coronary artery bypass surgery. While strain of atrial tissue is known to induce atrial fibrillating impulses, less attention has been paid to potentially strain-promoting values during the peri- and post-operative period. This study aimed to determine the association of peri- and post-operative volume substitution with markers of cardiac strain and subsequently the impact on POAF development and promotion.

A total of 123 (45.4%) individuals were found to develop POAF. Fluid balance within the first 24 hours after surgery was significantly higher in patients developing POAF as compared to non-POAF individuals (+1129.6 mL [POAF] vs +544.9 mL [non-POAF], P = .044). Post-operative fluid balance showed a direct and significant correlation with post-operative N-terminal pro-brain natriuretic peptide (NT-ProBNP) values (r = .287; P = .002). Of note, the amount of substituted volume significantly proved to be a strong and independent predictor for POAF with an adjusted odds ratio per one litre of 1.44 (95% CI: 1.09-1.31; P = .009). In addition, we observed that low pre-operative haemoglobin levels at admission were associated with a higher need of intraoperative transfusions and volume-demand.

Substitution of larger transfusion volumes presents a strong and independent predictor for the development of POAF. Via the observed distinct association with NT-proBNP values, it can reasonably be assumed that post-operative atrial fibrillating impulses are triggered via increased global cardiac strain. Optimized pre-operative management of pre-existing anaemia should be considered prior surgical intervention in terms of a personalized patient care.