Central sleep apnea in congestive heart failure: prevalence, mechanisms, impact, and therapeutic options.

Heart failure due to left ventricular systolic dysfunction is a prevalent syndrome and associated with morbidity, mortality, and huge economic cost. According to reports from several laboratories, a large number of patients with heart failure have central sleep apnea. Central sleep apnea causes arousals and sleep disruption, alters blood gases, and increases sympathetic activity. The pathophysiological consequences of central sleep apnea could adversely affect left ventricular structure and functions and worsen prognosis of heart failure. Several treatment options, including use of nocturnal supplemental oxygen, positive airway pressure devices, and theophylline have been systematically studied and have been shown to improve central sleep apnea. Long-term studies, however, are necessary to determine the impact of therapy on natural history of left ventricular systolic dysfunction.