Pressure Transients Occurring in Diastole in the Central Aorta

From the observations noted and from physical considerations, the following may be concluded: Cardiac events of sufficient energy content to cause sudden displacement of the heart and great vessels give rise to pressure transients that may be seen in all chambers if carefully looked for. These are, in reality, "acceleration" waves superimposed upon otherwise smooth pressure functions. Such an oscillation occurs normally at the time of isometric ventricular contraction. The energy content of isometric ventricular contraction results in an induced pressure wave in all chambers, but is most prominently seen in the low pressure atria as the "c wave, " and in the aorta and pulmonary artery as small, relatively high frequency, presystolic impulses. The event is obscured in the ventricles by the rapidly rising intraventricular pressure but may be identified when the ventricular pressure is differentiated. Under pathological circumstances, atrial contraction and early ventricular filling may result in peripherally recordable pressure deflections.