Cardiovascular effects of continuous positive airway pressure in patients with heart failure and obstructive sleep apnea

BACKGROUND: Obstructive sleep apnea subjects the failing heart to adverse hemodynamic and adrenergic loads and may thereby contribute to the progression of heart failure. We hypothesized that treatment of obstructive sleep apnea by continuous positive airway pressure in patients with heart failure would improve left ventricular systolic function. METHODS: Twenty-four patients with a depressed left ventricular ejection fraction (45 percent or less) and obstructive sleep apnea who were receiving optimal medical treatment for heart failure underwent polysomnography. On the following morning, their blood pressure and heart rate were measured by digital photoplethysmography, and left ventricular dimensions and left ventricular ejection fraction were assessed by echocardiography. The subjects were then randomly assigned to receive medical therapy either alone (12 patients) or with the addition of continuous positive airway pressure (12 patients) for one month. The assessment protocol was then repeated. RESULTS: In the control group of patients who received only medical therapy, there were no significant changes in the severity of obstructive sleep apnea, daytime blood pressure, heart rate, left ventricular end-systolic dimension, or left ventricular ejection fraction during the study. In contrast, continuous positive airway pressure markedly reduced obstructive sleep apnea, reduced the daytime systolic blood pressure from a mean (+/-SE) of 126+/-6 mm Hg to 116+/-5 mm Hg (P=0.02), reduced the heart rate from 68+/-3 to 64+/-3 beats per minute (P=0.007), reduced the left ventricular end-systolic dimension from 54.5+/-1.8 to 51.7+/-1.2 mm (P=0.009), and improved the left ventricular ejection fraction from 25.0+/-2.8 to 33.8+/-2.4 percent (P<0.001). CONCLUSIONS: In medically treated patients with heart failure, treatment of coexisting obstructive sleep apnea by continuous positive airway pressure reduces systolic blood pressure and improves left ventricular systolic function. Obstructive sleep apnea may thus have an adverse effect in heart failure that can be addressed by targeted therapy.