Grant: CIHR Fellowship

The heart is a pump that must both fill and empty effectively to move blood; if it cannot move enough, heart failure may ensue. Heart failure affects ~600,000 Canadians and half of these individuals have a form where the heart stiffens, which impairs its ability to fill. This form of heart failure particularly affects females and older adults. When people exercise, extra blood returns to the heart. The healthy heart can easily fill and move this extra blood to the muscles. However, when the heart's ability to fill is impaired, the extra blood can back up and pool in the lungs, like how rain causes water levels to rise behind a dam. Blood pooling in the lungs makes people feel breathless, although we do not fully understand why, and this form of heart failure has a high risk of hospitalization and death, but we have few effective treatments. Exercise is one of the few treatments that works well if enough exercise is performed regularly. However, many people with this form of heart failure can only tolerate a small amount before stopping due to severe breathlessness, which can put them off from exercising regularly. Our goal is to help these people feel less breathless and perform more exercise. We will use a novel form of stationary cycling with a plastic chamber around the lower body that seals at the waist like a kayak. The chamber can apply suction to the lower body during exercise which will reduce how much extra blood returns and prevent the heart and lungs from being overloaded. Subjects will perform 2 exercise tests for as long as possible with or without light suction. In each, we will record how long they exercise and ask them to rate how breathless they feel. We will also study their breathing pattern, using a mouthpiece and pressure sensor, and heart function, using ultrasound imaging. This work will help adults with heart failure exercise more and improve their health, and help researchers understand what causes breathlessness and develop new treatments.