CPAP should not be used for central sleep apnea in congestive heart failure patients.

399 B oth sleep apnea and congestive heart failure are common disorders. However, systolic heart failure appears to be the most common cause of central and perhaps obstructive sleep apnea. Obstructive sleep apnea is also common in isolated diastolic heart failure and may contribute to the progression of left ventricular remodeling and perhaps play a causative role. 1,3-6 However, prevalence and impact of sleep apnea have been most systematically studied in systolic heart failure, and a number of reports show a high prevalence of both central and obstructive sleep apnea in this disorder. It is generally assumed that these disordered breathing events, via neurohormonal stimulation, oxidative stress, and activation of redox-sensitive genes and inflammation, contribute to progressive remodeling of cardiac chambers and eventually to morbidity and mortality of heart failure patients. If true, treatment of sleep apnea should result in reversal of its pathophysio-logical consequences and in reverse remodeling of cardiac chambers , and eventually in improvement in morbidity and mortality of patients with heart failure. Treatment of obstructive sleep apnea in heart failure is generally the same as the treatment of this disorder without heart failure, and application of CPAP is the treatment of choice. Two random-ized but short-term (1 to 3 months) studies 12,13 with CPAP showed improved left ventricular ejection fraction in patients who have obstructive sleep apnea with left ventricular systolic dysfunction. However, no long-term mortality studies have been performed. Similarly, in patients with diastolic heart failure, treatment of obstructive sleep apnea with CPAP has resulted in reverse remodel-ing of ventricular morphology and improved function. In contrast to treatment of obstructive sleep apnea where application of nasal CPAP invariably results in virtual elimination of obstructive disordered breathing events, treatment of central sleep apnea in systolic heart failure is difficult, 1,2,6 and response to therapy could be variable. There are several options including use of positive airway pressure devices, nocturnal administration of oxygen , and medications such as theophylline and acetazolamide. Carefully executed short-term double-blind placebo-controlled trials have been performed with oxygen, 14 theophylline, 15 and acetazolamide. 16 These studies show considerable improvement in sleep apnea and desaturation. Oxygen has been studied most extensively. These studies show a decrease in sympathetic activity 19,20 and improvement in left ventricular ejection fraction. 21 However, only CPAP has been subjected to a long-term mortality trial. Early studies of CPAP to treat central sleep apnea in systol-ic heart failure showed differing …