Depressed Myocardial Contractile Reserve in Patients With Obstructive Sleep Apnea Assessed by Tissue Doppler Imaging With Dobutamine Stress Echocardiography

Background Hypoxia has been suggested to affect myocardial contractile function in patients with obstructive sleep apnea (OSA). We sought to determine whether myocardial contractile reserve (MCR), as evaluated by echocardiographic tissue Doppler imaging with dobutamine stress (TDDS), might be depressed in OSA patients. Methods Thirty patients with suspected OSA (25 men and 5 women; mean age, 51 ± 11 years [± SD]) underwent overnight polysomnography and TDDS. Peak myocardial systolic velocity (Sm) and peak myocardial early diastolic velocity (Em) in the 12 myocardial segments of the left ventricular (LV) walls were averaged, and the mean Sm and Em during TDDS were compared between patients with apnea-hypopnea index (AHI) Results In both groups, Sm increased dose dependently during TDDS. However, the relative increase in Sm was significantly lower in group 2, resulting in a lower value of MCR (5.5 ± 1.2 cm/s vs 7.4 ± 1.3 cm/s, p r = − 0.67, p r = 0.53, p r = − 0.46, p Conclusions OSA can affect MCR, implying an etiologic contribution from repetitive hypoxic events. TDDS could identify subtle abnormalities of OSA-related cardiac involvement.