[Echocardiographic analysis of cardiac size and function in patients with severe obstructive sleep apnea]

The purpose of this study was to determine usefulness of non invasive echocardiographic measurements in patients with severe obstructive sleep apnea (OSA). Diagnosis of OSA was established by polysomnography. We investigated 18 patients (16M, 2F), mean age 45 +/- 10 years, mean weight 114 +/- 16 kg and mean apnea/hypopnea index 69 +/- 23. Two-dimensional (2D) and Doppler echocardiography (DOP) was used to assess: 1. Systolic function of left ventricle by determination of cardiac output (CO), ejection fraction (EF), 2. Diastolic function of left ventricle by calculation of mitral early diastolic velocity to arterial velocity ratio (Ev/Av) and atrial flow to total mitral flow ratio (AF/Tf), 3. Right ventricle thickness in systole (RVWS) and diastole (RVWD), and its diastolic diameter (RVD), 4. Pulmonary arterial pressure (PAP) by evaluation of acceleration time in the pulmonary artery (ACT) and tricuspid regurgitation jet velocity (TR). Results (mean +/- SD): Co 6.67 +/- 2.0 L/min, EF 44 +/- 5.6%, RVWS 10.9 +/- 1.3 mm, RVWD 6.7 +/- 1.1 mm, RVD 30.3 +/- 2.8 mm, Ev/Av 1.22 +/- 0.39, Af/Tf 0.38 +/- 0.11, AcT 121.4 +/- 20.3 ms. These data confirm that intermittent hypoxia and increased ventricular afterload cause both systolic and diastolic left ventricular dysfunction. Right ventricular hypertrophy found despite normal resting, wake, PAP could be probably attributed to transient pulmonary hypertension during repeatable nocturnal hypoxic episodes.