Longitudinal ventricular systolic dysfunction in patients with very severe obstructive sleep apnea: A case control study using speckle tracking imaging

OBJECTIVE: Obstructive sleep apnea (OSA) is a prevalent condition that is increasingly recognized to be associated with cardiovascular disease. We aimed to investigate the subclinical systolic ventricular dysfunction of patients with OSA using novel speckle tracking echocardiographic (STE) techniques. METHODS: This study included 31 patients of polysomnography proven very severe OSA [Apnea Hypopnea Index(AHI) >40] and an equal number of matched population with no OSA as controls. All the study participants underwent a detailed conventional and tissue Doppler strain echocardiogram in addition to STE. RESULTS: There was no significant difference in conventional ventricular systolic function parameters including left ventricular (LV) ejection fraction, and myocardial performance index of left ventricle. Diastolic function was significantly reduced in patients with OSA as compared to controls. There was no difference in global circumferential strain or time to its peak between the two groups. However global longitudinal LV strain (GLS) was significantly reduced in patients with OSA (p < 0.01). Similarly time to peak longitudinal strain was prolonged in the OSA group as compared to controls. Segmental analysis revealed that the longitudinal strain abnormalities were more pronounced in the apical and mid segments of LV. AHI remained the only significant predictor of GLS in these patients. CONCLUSION: Very severe OSA is associated with significant diastolic dysfunction as well as early systolic abnormalities as evidenced by abnormal global longitudinal strain. Sleep apnea severity as measured by AHI was the only significant predictor of abnormal longitudinal strain in these patients.