Forty-five patients with OSA and heart failure with reduced ejection fraction ( left ventricular ejection fraction 35.89.7 % [ meanSD ] ) were evaluated with the use of echocardiography and 11C-acetate and 11C-hydroxyephedrine positron emission tomography before and 6 to 8 weeks after randomization to receive short-term CPAP ( n = 22 ) or no CPAP ( n = 23 ) .