A third of people diagnosed with heart failure die within the first year. The survivors have severely impaired quality of life because even day to day menial activities leave them breathless and incapacitated. Current treatment options include cardiac pacemakers which help to improve the pumping capacity of the heart. However, these pacemakers lead to fixed changes in heart rate, whereas in reality heart rate is rarely static. Heart rate fluctuates with breathing, and this variability is prominent at birth but lost with the development of heart disease. We will utilise a novel cardiac pace-making approach to re-introduce breathing induced heart rate variability. We will test whether this approach improves the pumping capacity of the heart in an animal model of depressed heart function. This clinically-relevant research will represent a significant step in the development of novel cardiac pacing strategies.