Heart failure and sleep apnea.

leep apnea has an association with various cardiovascular diseases and generally, it is classified as either obstructive sleep apnea (OSA) or central sleep apnea (CSA). OSA is a well-known trigger of cardiovascular diseases, whereas CSA is associated with cardiac pathologies that could further worsen prognosis. CSA, rather than OSA, is common in patients with heart failure. However, OSA and CSA often coexist in such patients. OSA is estimated to occur in approximately 10–40% of heart failure patients.1–4 Previous studies have reported that common characteristics of patients with OSA and heart failure are obesity, snoring or old age. Sleep-related upper airway collapse is the pathophysiology of OSA. The inspiratory effort against the occluded upper airway during sleep increases the negative intrathoracic pressure, which leads to an increase of preload (venous return) and transmural ventricular pressure. Intermittent hypoxia and sympathetic nerve activation during sleep also cause deterioration of cardiac function. These factors play a role in worsening heart failure.