Evaluation of subclinical left ventricular systolic dysfunction in patients with obstructive sleep apnea by automated function imaging method; an observational study

OBJECTIVE: We aimed to evaluate the subclinical left ventricular (LV) systolic dysfunction with the automated function imaging method (AFI) based on speckle tracking echocardiography (STE) in obstructive sleep apnea patients (OSA) with normal left ventricular ejection fraction (LVEF) and without any confounding disease that can cause myocardial dysfunction. METHODS: Twenty-one healthy individuals and 58 OSA patients were included in this observational cross-sectional study. According to the severity of disease, OSA patients were examined in three groups; mild, moderate and severe OSA. Apical 2-, 3- and 4- chamber images were obtained for AFI evaluation. The global systolic longitudinal strain (GLS) values were determined for each view, and averages of these were used in comparison of the patient groups. One-way ANOVA, Kruskal-Wallis, Pearson correlation tests and linear regression analysis were used for statistical analysis. RESULTS: The GLS values of the OSA patients were lower than of the healthy individuals and these values were decreased along with the OSA severity (Healthy:-25.58±-2.16%, Mild:-23.93±-3.96%, Moderate:-21.27±-2.60%, Severe:-16.94±-2.66%, respectively). The difference was significant between moderate OSA patients and healthy individuals, and significant between severe OSA patients and all other groups (p<0.03). The apnea-hypopnea index was found to be correlated with the GLS (β=-0.659, 95% CI: 0.09-0.17, p<0.001). CONCLUSION: Longitudinal LV mechanics in OSA patients with normal LVEF are deteriorated in the subclinical stage being associated with the severity of disease. AFI can be used as an effective and safe method in the determination of subclinical myocardial dysfunction in OSA patients, because it is semi-automated and easy to use with a short analysis time.