Paradoxical association between lipoprotein cholesterol levels and left atrial function in hypertensive diabetic patients: A speckle tracking study

Background Studies have shown that subclinical left atrial (LA) dysfunction can be diagnosed with two-dimensional speckle tracking echocardiography (2D-STE). Although low-density lipoprotein cholesterol (LDL-C) is a risk factor for cardiovascular diseases, recent studies have reported a paradoxical relationship between LDL-C level and atrial fibrillation. In this study, we investigated the relationship between LDL-C levels and LA function. Methods In 168 patients with the diagnosis of hypertension and diabetes, transthoracic echocardiography with LA 2D-STE was performed. The patients were then divided into two groups: normal LA-strain (n = 94) or impaired LA-strain (n = 74). The relationship between LDL-C and LA function was analyzed. Results Patients with impaired LA-strain had higher body mass index (BMI) (p = 0.029), higher statin usage (p = 0.003), and lower LDL-C levels (p = 0.001) than patients with normal LA-strain. They also had lower left ventricle ejection fraction (LVEF) (p = 0.047) and higher E-wave velocity (mitral e, m/s) (p = 0.020). Multivariate logistic regression analysis showed that lower LDL-C (p = 0.034), higher BMI (p = 0.004), lower LVEF (p = 0.004), and higher E-wave velocity (p = 0.003) values were independently associated with impaired LA-strain. The area under the receiver operating curve of LDL-C in predicting impaired LA-strain was 0.645 (0.564-0.730, p < 0.05). LDL-C <= 112.5 mg/dl was found to be the optimal cut-off value with 74.5% sensitivity and 51.2% specificity in predicting impaired LA strain. Conclusion In patients with hypertension and diabetes, LDC-C levels are moderately but independently and paradoxically associated with impaired LA function assessed by 2D-STE.