Studies of ultralow-frequency displacement ballistocardiogram in hypertension

Abstract

I. Clinical Observations 1. The IJ value, JM value and JM/IJ ratio have been measured as the quantitative expression of ultralow-frequency displacement ballistocardiograms in 259 hypertensive pa-tients and in 124 healthy persons. 2. In cases with arterial hypertension including three cases of polycythemia rubra vera, were observed the ascending dominant waves with a remarkably small IJ and a tall JM. 3. In normal adults, JM/ IJ ratio was proved to be 2.2-2.3 in all ages, however, a tendency to decrease was observed in IJ, and JM values. 4. In experimental hypertension (induced by noradrenaline injection) too, there was seen a decrease of IJ value and an increase of JM/ IJ ratio. Among the hypertensive cases with an exceptronally low JM/IJ ratio, a dilatation of the ascending aorta and aortic arch was detected in most cases. 5. The main factor increasing JM/IJ ratio was a decrease of IJ, which was especially influenced by arteriosclerosis and by an increase of systolic blood pressure. 6. No definite correlation was noted, among ECG, serum cholesterol level and eye-ground findings. 7. An obvious positive correlation was observed between the JM/IJ ratio and the low-/ high-frequency component ratio in the harmonic analysis of the pulse waves. 8. On the ultralow frequency ballistocardiogram, was noticed a largezr headward deflection in displacement of the body in each heart beat. The damping of this displacement might be considered to be a precipitating factor of the cerebral vascular lesions. II. Model Experiments 1. An experimental ultralow-frequency ballistocardiograph was designed and constructed. The apparatus consisted of the hammock-shaped bed, weighing 1.2 Kg and the natural frequency of the system being 0.23 cps, the damping being 4.1 per cent of the critical value, when the bed was loaded with 8Kg weight. 2. In order to search for the component of displacement wave and factors influencing the waves, a hydraulic circulatory model, was constructed, consisting from a glass flask as the heart and a rubber tube as the aorta. 3. Displacement wave was proved to be influenced by cardiac force, features of the blood vessel wall and blood pressure etc., and an especially close relationship was noticed between the shape of displacement wave and the elasticity of the aorta. 4. The ascending aorta and the aortic arch were proved to be the very parts which affected the displacement curves.