Max dD/Dt: A Novel Parameter to Assess Fetal Cardiac Contractility and a Substitute for Max dP/Dt

Abstract Aortic pulse waveforms are composed of a forward wave from the heart and a reflection wave from the periphery. We focused on this forward wave and suggested a new parameter, the maximum slope of aortic pulse waveforms (max dD / dt ), for fetal cardiac contractility. Max dD / dt was calculated from fetal aortic pulse waveforms recorded with an echo-tracking system. A normal range of max dD / dt was constructed in 105 healthy fetuses using linear regression analysis. Twenty-two fetuses with suspected fetal cardiac dysfunction were divided into normal and decreased max dD / dt groups, and their clinical parameters were compared. Max dD / dt of aortic pulse waveforms increased linearly with advancing gestational age ( r  = 0.93). The decreased max dD / dt was associated with abnormal cardiotocography findings and short- and long-term prognosis. In conclusion, max dD / dt calculated from the aortic pulse waveforms in fetuses can substitute for max dP / dt , an index of cardiac contractility in adults.