体温による制御機構を有するペースメーカの実験的研究

抄録

Many kinds of cardiac pacemaker have been used for cases with A-V block. But, most of them cannot increase the rate like the natural heart even under physiological change of metabolism. It is the purpose of this study to make the more physiological pacemaker, which changes the rate to maintain the adequate cardiac output for metabolic needs, such as exercise, excitement, fever and other disease.
As the body temperature usually shifts following the metabolic change, it will be useful to control the pacing rate. On the basis of this idea, pacemakers with the feedback mechanism by the body temperature were implanted in dogs, and the thermistor used in the generator was put in the right atrium to detect the venous blood temperature. After the pyrogenic drug, 2-4-Dinitrophenol, was given to the animals by mouth, the blood temperature gradually rose to above 41°C, and the pacing rate changed from 198.8±2.0 beats/min. at 37°C to 257.6±2.6 beats/min. at 41°C, and the cardiac output also increased from 2.23±0.48l/min. at 37.0°C to 4.15±0.53l/mm. at 41.0°C. The group to which this pacemaker was applied increased the cardiac output more significantly than the group with the fixed rate pacemaker at the high blood temperature of 39.6°C or above. The thermistor implanted in the right atrium of a dog for one month was involved in the tissue of atrial wall, and still could detect the change of temperature promptly.
It is concluded that the pacemaker sensitive to the blood temperature changes the rate to deliver adequate cardiac output for metabolic needs, and that the sensor works for a long time after the implantation.