Holter Monitor

A small, portable device worn on a strap or belt that continuously records a person's electrocardiogram for an extended period, typically one to several days, so a physician can review the heart's electrical activity during ordinary daily life rather than only during a brief office visit. It is named for Norman Holter, who built early wearable electrocardiographic recording equipment in the United States beginning in the late 1940s, work that was refined over the following decade into a genuinely portable recorder practical for patients to wear while going about their day. Electrodes attached to the chest feed the heart's electrical signal to the recorder, which stores it for later analysis, or in newer designs transmits it, so that occasional irregular heartbeats that might never appear during a short recording in a doctor's office have a much better chance of being captured. The device remains a standard tool for diagnosing intermittent arrhythmias and for judging whether symptoms such as palpitations, dizziness, or fainting coincide with an abnormal heart rhythm.