Biomed story songAmbulatory ECG (the Holter monitor)
The Backpack Heart
Helena, Montana, after the war: a physicist wants to record a heart while a person moves, so he straps a radio ECG to his back and rides a bike. The backpack shrinks into the monitor patients wear today.
A biomed story song. Diagrams are simplified to tell the story; it is not a service procedure.
The story behind it: Ambulatory ECG (the Holter monitor)
Norman Jefferis Holter, a biophysicist working from a laboratory in Helena, Montana, wanted to record the heart during everyday life rather than only with a patient lying still. In the late 1940s he demonstrated a radio-transmitted electrocardiogram worn as a heavy backpack, recording his own heart while exercising.
Over the following years the equipment shrank to a portable tape recorder, and the ambulatory ECG recorder, known as the Holter monitor, became commercially available in the early 1960s. Today small wearable recorders and patches capture a day or more of heart rhythm while patients go about their lives.
Reviewed November 1, 2026. General information, not a service procedure: follow the manufacturer's instructions and your facility's policy.
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