Norman Jefferis "Jeff" Holter was an American biophysicist who invented the Holter monitor, a portable device for continuously monitoring the electrical activity of the heart for 24 hours or more. Holter donated the rights to his invention to medicine.
Norman Holter
A Holter monitor
In medicine, a Holter monitor is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring for at least 24 hours.
3-lead Holter monitor
Atrial fibrillation recorded by a Holter monitor
Screenshot of Holter ECG software
A 5-lead placement EASI configuration Holter monitor