Cardiovascular implications of sleep apnea in patients with congestive heart failure.

Recent epidemiologic studies indicate that approximately 40 to 50% of stable patients with congestive heart failure (CHF) suffer from either obstructive sleep apnea (SA) or Cheyne-Stokes respiration with central SA. In either type of sleep apnea, several mechanisms contribute to significant mechanical and adrenergic stresses upon the failing myocardium. These include hypoxemia, reductions in intrathoracic pressure, rises in systemic arterial pressure, increases in left ventricular afterload, and arousals from sleep worsening the sleep architecture. Consequently, sympathetic activation and parasympathetic withdrawal are the hallmark of sleep-related sleeping disorders that contribute to the progression of heart failure and may adversely affect its prognosis. On the other hand, recent studies indicate that successful treatment of either type of SA with continuous positive airway pressure in patients with CHF results in objective and subjective improvement in the severity of heart failure increases in left ventricular ejection fraction, and reductions in sympathetic nervous system activity. Therefore, the early diagnosis and specific treatment of either obstructive or central SA in patients with CHF is highly warranted.