Characterization of dynamic left ventricular systolic and diastolic function in patients with obstructive sleep apnea syndrome with preserved left ventricular ejection fraction

Abstract

Repetitive hypoxia due to sleep-induced apnea adversely affects the interaction between myocardial oxygen demand and supply in OSAS patients, resulting in the development of subclinical cardiac dysfunction. We hypothesized that patients with OSAS with preserved left ventricular (LV) ejection fraction would have abnormalities in LV diastolic function and/or deformation, with increased dynamic diastolic stiffness compared with healthy controls. Conventional echocardiography, Doppler myocardial imaging (DMI) and two-dimensional speckle tracking echocardiography (2DSTE) of LV longitudinal deformation, at rest and during supine bicycle exercise stress echocardiography, were performed in 25 patients (53.1± 14.2 y; 18 males) affected by moderate to severe OSAS with preserved (> 50%) EF and 25 age and sex-matched healthy controls. Despite comparable EF, there were significant differences in terms of LV global longitudinal strain (GLS) both at rest and at peak exercise between the two groups (p<0.001). In addition, both pulmonary artery systolic pressure and E/E′ ratios increase during effort were higher in OSAS vs healthy subjects (p<0.0001). The best correlation with exercise capacity (peak watts reached) was E/E′ at peak stress (r = −0.68, P < 0.0001). On multivariate analysis, independent associations of LV E/E’ at peak effort with blood lactate concentration, apnea–hypopnea index, and LV GLS were evidenced. A therapy aimed at increasing LV diastolic function reserve could improve the quality of life and the effort tolerability of these subgroup of patients.