1975: And the Changes To Come
Heart Alarm. Heart victims' lives might be saved with these electronic devices, demonstrated by inventor Morris Tischler. The "Cardiac Pacer" is worn by heart patients and automatically emits electrical stimulants in the event the heart falters. The "Cardiac Monitor" keeps track of the heart rate, and, in the event of trouble, activates the Pacer, sets off a high-pitched alarm, and broadcasts a special signal to a receiver carried by the doctor. The signal broadcasts for a distance of two and a half miles. Unit is for bedside use, either at home or in a hospital, and is likely to be standard equipment of heart specialists in another few years.
from 1975: And the Changes To Come by Arnold B. Barach