初期のバッテリー駆動型埋め込み型ペースメーカーの設計分析：リズム管理の先駆

In 1958 and 1960, Dr. Rune Elmqvist (Sweden) and Wilson Greatbatch (USA) independently developed the first battery-powered implantable cardiac pacemakers. Though unaware of each other's work, both pioneers employed a transistorized blocking oscillator as the core of their pacemaker design, enabled by the recent availability of silicon transistors. This paper analyzes the convergent design principles of these early devices, comparing circuit architectures, power sources, and clinical considerations. Elmqvist's use of rechargeable nickel-cadmium batteries with transcutaneous charging contrasted with Greatbatch's strategy of primary mercury-zinc cells, each reflecting distinct engineering priorities. To better understand these designs, we constructed characterization breadboards, as well as reconstructed functional, visually faithful replicas of three historical devices: Elmqvist's 1958 prototype, Elema-Schönander 1959's model EM135, and the 1960 Greatbatch-Chardack pacemaker. Our engineering analysis and replica testing demonstrate the elegant simplicity of these pioneering systems, offering insights into the early intersection of electronics and implantable medical therapy.