[Sleep apnea syndrome and heart failure].

More than half of all patients with stable heart failure are affected by sleep apnea syndrome. The mechanism of apnea may be either obstructive, by collapse of the upper airways, or central with nocturnal Cheyne-Stokes respiration. Changes in intrathoracic pressure, awakening and hypoxemia all lead to an increase in left ventricular afterload and to sympathetic activation, which can aggravate heart failure and prognosis. Treatment with positive pressure ventilation improves symptoms as well as cardiac function and prognosis. Sleep respiratory disorders are underdiagnosed and undertreated in patients with stable heart failure. To improve management of sleep apnea, patients with stable heart failure should be screened with small outpatient oximeters.