In the working heart perfusion mode, the flow of perfusate mimics the flow of blood in situ. The perfusate enters the left atrium via the pulmonary vein and is pumped into the left ventricle then ejected into the aorta, against a resistance that mimics the global resistance of the body (afterload).
As the name implies, this technique allows the heart to perform its physiological pumping action, i.e. it performs pressure/volume work. Therefore, it provides a complete analysis of heart function and can be used to study cardiac metabolism, long-term pathology or ischemia-reperfusion.