Abstract Body (Do not enter title and authors here): Background: Left ventricular (LV) global longitudinal strain (GLS) in an outpatient setting is an established marker of atrial fibrillation and adverse outcomes. However, the implications of dynamic LV GLS measurements (delta GLS) by intraoperative transesophageal echocardiography (TEE) during cardiac surgery and postoperative outcomes are unknown.
Research Question: This study aims to evaluate the association of delta GLS (the difference between postoperative and preoperative GLS) with new onset of postoperative atrial fibrillation (POAF).
Methods: This post-hoc cohort study is from PALACS (Posterior Left Pericardiotomy for the Prevention of Atrial Fibrillation after Cardiac Surgery) trial. Patients with intraoperative TEE images analyzable for LV GLS were included. Images were acquired before sternotomy (preoperative TEE) and after chest closure (postoperative TEE), according to a prospective protocol. Strain analysis was performed using commercial software; automatic tracking was edited to ensure accurate border tracking (Figure 1). The primary outcome was a new onset of POAF. Secondary outcomes included morbidity and mortality (Table 2A).
Results: A total of 363 patients were included (median age: 61.0 IQR [53.0-69.5]; 84 (23.1%) female). Median preoperative GLS was -18.1% [-19.5, -16.5] and median delta GLS was 0.3 [-1.1, 1.5]. POAF incidence was higher in patients with no strain improvement (32.2% vs. 20.4%, p=0.0015). For the secondary outcomes, antiarrhythmic and anticoagulation medications use was higher in patients with no strain improvement versus strain improvement (30.9% vs 19.9%, p= 0.02; 15.1% vs. 6.6%, p=0.01). In the multivariable model (Table 2B) preoperative LV GLS (HR: 0.83; 95% CI: 0.70; 0.99; p=0.03) and delta LV GLS (HR: 0.90; 95% CI: 0.82; 1.00; p=0.04), both remained independently associated with POAF.
Conclusion: The change in LV GLS and preoperative GLS were associated with new onset of POAF in cardiac surgery patients. Future studies should focus on improving intraoperative strategies, aiming at optimizing LV function and thus, clinical outcomes.