Assessment of right ventricular function in obstructive sleep apnea syndrome and effects of continuous positive airway pressure therapy. a pilot study

Background. It is known that obstructive sleep apnea syndrome (OSAS) can affect right ventricular (RV) performance even in the absence of systemic hypertension and other known cardiac or obstructive pulmonary disease. The purpose of the present study was to assess RV function in OSAS by three-dimensional (3D) echocardiography and speckle tracking echocardiography (STE) and evaluate changes after continuous positive airway pressure (CPAP) treatment. Methods. Thirty-seven patients with OSAS without comorbidities and thirty controls were studied with 3D-echocardiography and STE. Fifteen patients underwent CPAP therapy and were studied before and after treatment. RV 3D ejection fraction was calculated. Peak-systolic strain was determined. RV dyssynchrony was defined as standard deviation of the six time to peak-systolic strain values. Results. 3D RV ejection fraction was lower and RV dyssynchrony was greater in patients with moderate-severe OSAS compared to controls both in the presence and absence of pulmonary hypertension. 3D RV ejection fraction and RV dyssynchrony were independently associated with apnoea-hypopnea index. Patients treated with CPAP had significant changes in RV parameters. Conclusions. 3D RV ejection fraction and RV dyssynchrony were abnormal in OSAS patients compared to controls and associated with OSAS severity. RV-3D-STE abnormalities improved after chronic application of CPAP.