The sleep apnoea syndromes.

In recent decades, awareness of sleep apnoea syndromes has increased both in the public mind and among medical professionals. As a result, the number of patients referred for evaluation to a sleep clinic has increased dramatically. The term sleep ‘disordered breathing’ comprises the whole continuum, from chronic snoring to obstructive sleep apnoea and the so-called ‘Pickwick syndrome’. Obstructive sleep apnoea syndrome is the most common type, occurring in 5–20% of adult men, although only about 20% of these individuals has symptoms. It is characterized by recurring episodes of upper airway obstruction during sleep. This condition is usually associated with loud snoring and arousals, resulting in marked sleep fragmentation. Increased daytime sleepiness is an important symptom. The recurrent hypoxaemia and hypercapnia may lead to both pulmonary and systemic hypertension, cardiac arrhythmias and decreased survival. The diagnosis of sleep apnoea syndrome is made by performing polysomnographia. However, the devices used vary in precision and reliability and there is also considerable variation in criteria for diagnosis. At present, sleep apnoea syndromes are easily treatable. The objective of this review is to draw attention to the relationship of sleep apnoea syndromes with symptoms and signs of cardiovascular dysfunction. A description is given of history, definitions, clinical features, epidemiology, pathophysiology and treatment of the sleep apnoea syndromes.