The significance of ten unique characteristics of the cardiovascular system has been demonstrated by clinical observations, cardio-bypass data, animal mechanical heart replacement experiments, and a simulated cardiovascular model. All of the evidence validates that:
- The cardiovascular system is a circle containing a mean cardiovascular pressure dependent upon volume and compliance.
- The heart is a passively filling pump.
- Atria increase cardiac output by causing continuous venous flow to the intermittently contracting ventricles, not by pumping up the ventricles.
- Circulation rate is normally determined by the extra-cardiac factors: mean cardiovascular pressure and inlet impedance.
- It is only during heart failure that the heart is the regulator of cardiac output.