The purpose of this study is to determine whether patients with obstructive sleep apnea have any changes in left ventricular function and structure after 06 months of continuous positive airway pressure treatment.

Several studies have been suggesting that Obstructive Sleep Apnea contributes to deterioration of left ventricular diastolic function. It may be associated to increased risk of cardiovascular events. We hypothesized that morphological and functional left ventricular changes might be reverted after treatment with Continuous positive airway pressure.

Inclusion Criteria:

• Apnea-hypopnea index higher than 5 events per hour

Exclusion Criteria:

• Body mass index higher than 40 kg/m2