Cardiovascular physiology, in its simplest form, can be summed up by two very basic equations: right = left and V = IR (where V indicates voltage, and IR indicates the product of current and resistance). The former equation states that, in the absence of shunt, the left heart can only pump what it receives from the right. The latter equation, Ohm’s law, is transposed in cardiology as pressure = flow × resistance. In vivo, of course, this relationship is far more complex as the pulmonary circulation is not a set of rigid pipes, and the flow is pulsatile. The mechanism of right ventricle (RV) contraction remains enigmatic, and fully characterizing the RV-pulmonary artery coupling relationship is difficult.1 The challenge to clinicians and scientists is to move beyond these very basic equations, while respecting their principles.