Obstructive sleep apnea hypopnea syndrome (OSAHS) is characterized by repetitive upper airway obstruction during sleep and it is commonly seen in the adult population, 4% in the men, 2% in the women. The most common nocturnal symptom is snoring while the most common daytime symptom is excessive daytime sleepiness. The gold standard in the diagnosis is polysomnography. Nasal continuous positive airway pressure is the most efficient therapy in the treatment and prevention of the disease. The OSAHS may cause cardiovascular complications in long-term, including systemic hypertension, pulmonary hypertension, congestive heart failure, arrhythmias, stroke and myocardial infarction. All these complications increase the morbidity and mortality of OSAHS.