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. We have used a novel cardiac pace-making approach to reintroduce breathing-induced heart rate variability and shown improvements in cardiac output. We will now test whether this approach improves respiratory imbalance and exercise tolerance in an ovine model of depressed heart function. This clinically relevant research will represent a significant step in the development of novel cardiac pacing strategies.