Effect of Gastric Myoelectric Activity on Photoplethysmographic Signals

Understanding the hemodynamic interactions of a non-cardiac system with the main circulatory system is a challenging task in modern medicine. In this study the effect of gastric myoelectric activity (GMA) on peripheral blood volume pulse, acquired by photoplethysmographic (PPG) technique during fasting and postprandial states are analyzed using wavelets. PPG and Electrogastrogram (EGG) signals were acquired simultaneously from 8 healthy volunteers for 30 minutes duration in both states. In this study the power ratio (PR), which is the ratio between powers of the signal in fasting state to the postprandial state, was calculated and it changes significantly. The correlation coefficient was significantly higher (r = 0.93; P < 0.05) between PPG PR value and EGG PR value. PR is a good indicator of hemodynamic changes in the main circulatory system caused by stimulation of other subsystem. In future such analysis can be used as a diagnostic tool for gastric disorders which modulate the peripheral circulations.