Figure 32-5 Arterial blood pressure waveform produced by the summation of sine waves. The fundamental wave (top) added to 63% of the second harmonic wave (middle) results in a pressure wave (bottom) that resembles an arterial blood pressure waveform (box). (Redrawn from Mark JB: Atlas of Cardiovascular Monitoring. New York, Churchill Livingstone, 1998, Fig. 9-1.)