Sleep apnea and the heart.

The normal sleep-wake cycle is characterized by diurnal variations in blood pressure, heart rate, and cardiac events. Sleep apnea disrupts the normal sleep-heart interaction, and the pathophysiology varies for obstructive sleep apnea (OSA) and central sleep apnea (CSA). Associations exist between sleep-disordered breathing (which encompasses both OSA and CSA) and heart failure, atrial fibrillation, stroke, coronary artery disease, and cardiovascular mortality. Treatment options include positive airway pressure as well as adaptive servo-ventilation and phrenic nerve stimulation for CSA. Treatment improves blood pressure, quality of life, and sleepiness, the last particularly in those at risk for cardiovascular disease. Results from clinical trials are not definitive in terms of hard cardiovascular outcomes.