Statistical analysis
REGRESSION
This was an observational cross-sectional study. The predictor variables were LA strains. Potential covariates or confounders were LA volume index, LV function, right ventricular function, age, sex, body mass index (BMI), biochemical index, etc. The outcome variable was VOThe independent sample t test was used to compare data with a normal distribution between groups. Data that did not conform to a normal distribution were compared using the rank sum test. Linear regression was performed using VOReceiver operating characteristic (ROC) curve analysis was used to evaluate the area under the curve (AUC) for LA strain to predict impaired VOStatistical analysis was performed using STATA 17.0 (STATA Corp, College Station, TX, USA) and MedCalc 20.1.0 (MedCalc Software Ltd., Ostend, Belgium). All tests were two-tailed, and 