Fig. 4.

Coronary wave energies superimposed on the pressure-volume (PV) loop. a The cardiac cycle depicted as LV pressure (LVP) as function of volume (LVV), the end-diastole (ED), end-systole (ES), and dP/dT max and dP/dTmin (maximal rate of pressure increase and pressure decline, respectively) depicted on the PV loop. b The forward travelling compression wave (FCW) in the coronary artery originates when LV pressure equals aortic diastolic pressure (immediately prior to aortic valve opening) and terminates immediately prior to peak LV pressure. The forward expansion wave (FEW) originates when LV pressure equals aortic systolic pressure (peak LV pressure) and terminates during isovolumic relaxation at the point of dP/dT min (maximal LV rate of relaxation). c The backward compression wave (BCW) originates during isovolumic contraction and terminates immediately after aortic valve opening (when LV pressure exceeds aortic diastolic pressure). The backward expansion wave (BEW) originates on aortic valve closure, at end-systole, and terminates at minimum LV pressure. d Wave generation during the cardiac cycle. The black broken line represents end-systole, with standard deviation (red broken line). ED end-diastole, BCW backward compression wave, FCW forward compression wave, BEW backward expansion wave, ES end-systole, FEW forward expansion wave, ms milliseconds, s start, p peak, e end