Baseline intraoperative left ventricular diastolic function is associated with postoperative atrial fibrillation after cardiac surgery.

BACKGROUND: Detailed understanding of the association between intraoperative left atrial (LA) and left ventricular (LV) diastolic function and postoperative atrial fibrillation (POAF) is lacking. In this post-hoc analysis of the PALACS (Posterior Left Pericardiotomy for the Prevention of Atrial Fibrillation after Cardiac Surgery) trial, we aimed to evaluate the association of intraoperative LA and LV diastolic function as assessed by transesophageal echocardiographic (TEE) with POAF.

METHODS: PALACS patients with available intraoperative TEE data (n=402/420, 95.7%) were included in this cohort study. We tested the hypotheses that preoperative LA size and function, LV diastolic function, and their intraoperative changes were associated with POAF. Normal LV diastolic function was graded as 0 and with lateral e' velocity≥10 cm/s. Diastolic dysfunction was defined as lateral e' <10 cm/s using E/e' cut offs of grade 1 E/e'≤8, grade 2 E/e' 9 to 12, grade 3 E/e'≥13, along with 2 criteria based on mitral inflow and pulmonary wave flow velocities.

RESULTS: Two-hundred and thirty of 402 patients (57.2%) had intraoperative diastolic dysfunction. Posterior pericardiotomy intervention was not significantly different between the two groups. Ninety-nine of 402 patients (24.6%) developed POAF. Patients who developed POAF more frequently had abnormal LV diastolic function compared to patients who did not develop POAF (75.0% [n=161/303] versus 57.5% [n=69/99], p=0.004). Of the LA size and function parameters, only delta LA area, defined as pre-sternotomy - post-chest closure measurement was significantly different in the no POAF versus POAF groups on univariate analysis (-2.1 cm 2 [IQR -5.1, 1.0] versus 0.1 [IQR -4.0, 4.8]; p=0.028). At multivariable analysis, baseline abnormal LV diastolic function (OR 2.02; 95%CI 1.15-3.63; p=0.016) and pericardiotomy intervention (OR 0.46 [0.27;0.78]; 95%CI 0.20-0.78, p=0.004) were the only covariates independently associated with POAF.

CONCLUSION: Baseline preoperative LV diastolic dysfunction on TEE, not LA size or function, is independently associated with POAF. Further studies are needed to test if interventions aimed at optimizing intraoperative LV diastolic function during cardiac surgery may reduce the risk of POAF.