Abstract: Method and apparatus for analyzing the propagation of arterial pulse waves in a patient's circulatory system. The apparatus comprises R-wave detecting means for outputting an R-wave timing signal at the time of detection of the R-wave component contained in a detected electrocardiographic signal. A pulse wave peak detecting means is provided for outputting a peak timing signal at the time of the detection of a selected peak of the arterial pulse wave detected in the peripheral blood vessels of a patient's circulatory system. A pulse wave propagation time counter is provided for successively counting the time interval from the input of the R-wave timing signal to the input of the peak timing signal, and a pulse wave propagation time analyzer is provided for analyzing the distribution of pulse wave propagation times and other detected biophysiological parameters, from which an effective diagnosis of the condition of the patient's circulatory system can be made.

Abstract: A field effect transistor for use as an ion sensor has a P-type silicon substrate on which are formed a source region and a drain region. An N-type isolation diffusion layer is formed on the outer peripheral surface of the silicon substrate and this diffusion layer is surrounded by an insulation layer. According to this arrangement, even when the potential of the electrolyte has been raised to a level which is positive with respect to the silicon substrate, an electrical isolation is established by the reverse dielectric strength exhibited by the P-N junction.

Abstract: Apparatus for inspecting the electrical stimulation of a patients' heart. The apparatus includes a stimulation device in which electrical stimulating wave is generated by an electrical stimulation wave generating device for effecting pacing of a patients' heart in accordance with an externally set stimulation pattern impressed upon the wave and applied to the heart through a catheter, wherein intracardiac electrocardiogram signals are induced, amplified, and recorded on a recorder which is annexed to the stimulation device. The recorder is designed to commence the recording operation in response to a recording start signal in advance of the generation of the final electrical stimulation wave, and to stop the recording operation in response to the intracardiac electrocardiogram signal generated for the first time after the generation of the final electrical stimulation wave.