Electrocardiographs before 1910: Manufacturers and surviving instruments

Area of Science:

• Biomedical Engineering
• Medical History
• Instrumentation Science

Background:

• Early electrocardiographs required highly sensitive instrumentation due to the absence of electronic amplification.
• Willem Einthoven's 1903 string galvanometer revolutionized electrocardiography, enabling clinical diagnosis.

Purpose of the Study:

• To detail the history and technical aspects of a complete string galvanometer system in Lund, Sweden.
• To review the early commercial production and survival of string galvanometers made before 1910.

Main Methods:

• The Lund electrocardiograph was analyzed and compared to historical records and Einthoven's laboratory documentation.
• A survey of museum collections and manufacturers' archives was conducted to identify surviving early instruments.

Main Results:

• The 1909 Lund string galvanometer, built from Einthoven's designs, retains its core components.
• Commercial production was limited to Edelmann and Cambridge Scientific Instrument Company, with few surviving examples.

Conclusions:

• Complete early electrocardiographs are exceptionally rare.
• The Lund instrument is a significant surviving example, emphasizing the need for conservation of early biomedical technology.