During several decades of this century, the classical physiological studies on the cardiovascular system have greatly improved our knowledge on the function of this system under normal and pathological conditions. This knowledge was the basis of the breakthrough for diagnostic techniques like the Swan-Ganz catheter, coronary arteriography, left and right heart biopsies, and invasive measurements of contractility, as well as therapeutic tools including aortocoronary bypass surgery, percutanous transluminal coronary angioplasty, and a broad field of pharmacological interventions for the whole...