Left atrial strain analysis and new-onset atrial fibrillation in patients with ST-segment elevation myocardial infarction: A prospective echocardiography study.

BACKGROUND:New-onset atrial fibrillation (NOAF) is a well-known complication of ST-segment elevation myocardial infarction (STEMI), probably due to left atrial (LA) remodelling. LA strain (LAS) can predict NOAF in several cardiovascular diseases. OBJECTIVE:To assess whether LAS predicts NOAF in sinus rhythm patients with STEMI during hospitalization. METHODS:Adults with a STEMI and transthoracic echocardiography performed within 48hours of admission were included. LAS analysis, performed by automated software, recorded LAS during the reservoir phase (LASr), the conduit phase (LAScd) and the contraction phase (LASct). RESULTS:From May 2021 to November 2022, 175 patients were included, 21 (12%) of whom developed NOAF. NOAF patients were older (median [Q1-Q3]: 67 [59-80] vs 59 [51-67]years; P=0.006) and had a higher Thrombolysis In Myocardial Infarction scores (4 [2-7] vs 3 [1-4]; P=0.005). All LAS parameters were significantly impaired in NOAF patients, especially LASr (13.0% [10.5-28.4] vs 36.6% [29.0-44.9]; P=0.001). An LASr cut-off of 27% had a sensitivity of 81% and a specificity of 80% to identify patients with NOAF. In a multivariable model, LASr was significantly associated with NOAF (odds ratio 1.18, 95% confidence interval 1.09-1.26; P=0.003). The cumulative risk of NOAF during hospital stay was 30% (18-43 with LASr<27% and 4% [1.5-8.5] with LASr≥27% [P<0.0001]). CONCLUSION:NOAF is a frequent complication of STEMI. LASr seems helpful for identifying patients at high risk of NOAF during hospitalization.