A COMPARATIVE STUDY ON SEVERAL TYPES OF THRESHOLD ANALYZERS

• Published in: Jinko Zoki Vol. 6; no. 6; pp. 389 - 392
• Main Authors: TODO, Kageshige, KANEKO, Satoru, OHNO, Takemi, SUGIKI, Kenji, ASAI, Yasufumi, ABE, Tomio, KASHINO, Ryuji, WADA, Juro
• Format: Journal Article
• Language: Japanese
• Published: JAPANESE SOCIETY FOR ARTIFICIAL ORGANS 1977
• ISSN: 0300-0818; 1883-6097
• DOI: 10.11392/jsao1972.6.389

Seven types of threshold analyzers were studied. The voltage and current wave form of each analyzers were observed with an oscilloscope when the electrode impedance was turned 200 up to 1100 OHM. The voltage and current pulse out-put of the analyzers were also measured. Then, a clinical study for thresholds of cardiac stimulation in patients with a implanted pacing lead was obtained. The v-constant and the c-constant threshold analyzers which were made in the same Inc. were used for the same five patients, and the difference of the data between the v-constant and c-constant type were compared. Measurements were made at initial implantation by obtaining stimulation threshold at each of four stimulus pulse durations ranging from 0.25 to 2.0msec. Each analyzer has its own wave forms. The results of the measurements of the electrical threshold seem to be affected by the difference of the wave forms. The current pulse out-put of the v-constant analyzers increased and the voltage pulse out-put of the v-constant analyzers remained unchanged, when the electrode impedance was turned down. However, the voltage pulse out-put of the c-constant analyzers increased and the current pulse out-put of the c-constant analyzers remained stable, when the electrode impedance was turned up. When the different type analyzer is used, these differences between the v-constant and c-constant equipment may make an error on the patient with low electrode impedance. In fact, there are positive difference between the threshold data which were measured with the v-constant analyzer and the c-constant analyzer when they were used in the clinical study. When the threshold analysis is made, it is a satisfactory method if the same type of equipment (c-constant or v-constant) is available as an implanted generator.