Heart failure with reduced ejection fraction (HFrEF) is a serious condition that limits daily activities and often leads to hospital stays and early death. Many patients with HFrEF also have obstructive sleep apnea (OSA), a common but often undiagnosed condition where breathing repeatedly stops during sleep. This causes drops in oxygen, poor sleep, and stress on the heart, which can make heart failure worse.
The investigators are studying whether a device called a mandibular advancement device (MAD)-a mouthpiece worn during sleep that keeps the airway open-can help people with both HFrEF and moderate-to-severe OSA. This device is already approved to treat OSA and is often more comfortable and easier to use than a CPAP machine.
In our study, 328 patients in Singapore will be randomly assigned to use either the MAD or a sham device that looks the same but doesn't move the jaw. They will wear the device for 12 months. We will measure changes in a blood marker linked to heart failure severity, as well as exercise ability, blood pressure, sleep quality, and hospital visits.
The investigators hope this study will show that MAD is a simple and patient-friendly way to improve outcomes in people with heart failure.