The dynamic function of the atrial diastole of the heart and motion of venous valves in humans.

This study demonstrates dynamic function of atrial diastole for the first time in the history of medicine, following the revelation of ventricular function by Sir William Harvey. This study consists of two parts. First part is the study of humans and the discovery of the rhythmic opening and closing of venous valves in the femoral vein segment during each cardiac cycle under fluoroscopy. Its relationship to the right atrial diastole is discussed. Second part is an experimental model developed in a dog's heart. Experiments are conducted in an erect posture, in which the right atrium is partially and totally isolated physically and/or functionally. The right atrium was found to function as a suction pump, readily demonstrated on graphic curves by voluntary stretching of muscle fibers of the empty atrium, creating considerable negative pressure during diastolic function, and responsible for venous return to the heart. Motive forces in the venous return are common knowledge in present medical literature, but are limited to respiration and skeletal muscle contraction of the extremities. The discovery of the right atrium as a suction force due to stretching of muscle fibers during diastolic function, thereby creating negative pressure, represents a departure from the currently accepted paradigm established by Sir William Harvey (1576-1652), with the heart as an organ functioning solely by contraction of its chambers. This is the first time since then a fundamental new discovery concerning cardiac mechanical function has been made utilizing experimental evidence.