Cardiac lymphatics and cardiac lymph flow in health and disease

Heart being a highly dynamic organ, studies on its lymphatic system have lagged even further behind those of other organs. We now understand that the cardiac lymphatics are critical regulators of both cardiac interstitial balance and immunity. The movement of lymph through the heart and the pathways through which it moves through the layers of the heart tissue is propelled mainly by active rhythmic compression of the cardiac tissue and can be modified by alterations in lymphatic tone. Interruption of the progress of lymphatic outflow from the heart, either through injury or obstruction, can lead to serious problems with cardiac contractility and conduction. This chapter considers the structural adaptations of lymphatics in the heart, the significance of lymph flow in cardiac function and dysfunction, and provides some insights into how maintenance or restitution of lymphatic networks can be used clinically to preserve cardiac function particularly that associated with many existing and common surgical procedures.