A Novel Method for Sensitive Determination of Subclinical Left-Ventricular Systolic Dysfunction in Subjects With Obstructive Sleep Apnea

BACKGROUND: This study was to evaluate the subclinical left-ventricular (LV) systolic dysfunction with 2-dimensional speckle-tracking echocardiography in subjects with obstructive sleep apnea (OSA) with normal left ventricular ejection fraction and without any confounding disease that can cause myocardial dysfunction. METHODS: Nineteen healthy individuals and 60 subjects with OSA were included in this study. According to the severity of disease, OSA subjects were examined in 3 groups: mild, moderate, and severe OSA. LV apical views (for longitudinal strain) and short-axis views (for circumferential strain) were acquired for evaluation. Three-layer longitudinal strain values and circumferential strain values were determined for each view, and averages of these were used in comparison with other groups. RESULTS: Three-layer longitudinal strain values of the subjects with OSA were lower than those of the healthy individuals, and these values were decreased along with the OSA severity. The difference was significant between severe OSA and all other groups. Three-layer circumferential strain values of the OSA subjects were lower than those of the healthy individuals, and the difference was significant between the control group and all other groups. The apnea hypopnea index was found to be correlated with the 3-layer longitudinal strain (r = -0.74, P < .001; r = -0.72, P < .001; r = -0.69, P = <.001). CONCLUSIONS: Three-layer longitudinal and circumferential LV systolic functions in OSA subjects with normal left ventricular ejection fraction are deteriorated in the subclinical stage. Two-dimensional speckle-tracking echocardiography can be used as an effective method in the determination of subclinical myocardial dysfunction in subjects with OSA.