Three-dimensional analysis of systolic blood pressure and R-R interval: proposal of self-sounding spiral theory.
Having noted the findings that the frequency spectrum of fluctuation in blood pressure resembles that in R-R interval on ECG, and that both fluctuations are continuous time-related changes, we attempted three-dimensional analysis of blood pressure, R-R interval and time. The serial values in systolic arterial pressure and R-R interval which were simultaneously taken in 17 healthy volunteers (24.8 +/- 3.5 years old) were later analyzed using a personal computer. When dots of systolic pressure and R-R interval were plotted in order in a three-dimensional manner, they depicted spiral movements around an imaginary axis. The magnitude and angle of dot movement was then expressed quantitatively, by assuming the movements as a group of vectors. The vectors were uniformly distributed in four quadrants. The directions of the vector's connections were clockwise in about 75%, while their angles showed no particular tendency. Based on these three-dimensional morphological features of fluctuations in blood pressure and R-R interval, we propose a hypothesis called 'self-sounding spiral theory' for a mechanism preserving the cardiovascular homeostasis.