The Right Heart System

For many years, progress in the management of right heart failure has been hampered by two inter-related scientific phenomena. The first is the (now historical) dismissal of the right ventricle (RV) as a passive conduit. Right ventricular pump function was believed to be unnecessary, based largely on early observations that bypassing the RV (via right atrialpulmonary artery anastomoses) resulted in only small changes in central venous pressure without venous congestion; and cardiac output could be maintained by fluid loading despite electrical isolation of the RV free wall. The paradigm that arose from these experimental models has shaped the clinical practice of fluid loading for all forms of right heart failure. The second is the ‘cardio-centric’ approach to the right heart that remains prevalent today. Right heart failure is frequently conflated with RV failure. The interaction between the lungs, ventilation and the right heart is often neglected, as scientific discourse focussed on the ventricle. This chapter will discuss the physiology of the right heart system, drawing attention to systemic venous return, the RV itself, the pulmonary circulation and the interaction with the lungs, so-called heart–lung interaction.