Direct effects of pulse wave reflection may increase or decrease systolic blood pressure and stroke work

For decades, investigators have calculated antegrade and reflected pressure waves from measured aortic pressure and flow. Although the physics of reflection is well understood, there has been controversy concerning the effect of reflection on aortic pressure and stroke work. Two opposing views have arisen. In one view, reflection from the periphery is believed to increase systolic pressure and stroke work. In the other view, reflection, if it has an effect, decreases systolic pressure and stroke work. In an attempt to resolve this conflict, two popular arterial system models are applied. Both models reflect the same proportion of the antegrade pressure wave. The only difference between them is that one model includes an extra time delay between the antegrade and reflected waves. These two models yield opposite results. This exercise clearly illustrates that the direct effect of reflection depends on the timing of the reflected wave relative to the antegrade wave