ABSTRACT
Electrocardiogram (ECG) is the recording of the electrical activity generated by the heart on the body surface. It was originally observed by A. D. Waller in 1889 using his pet bulldog as the signal source and the capillary electrometer as the recording device. In 1903 W. Einthoven improvised the technology by using the string galvanometer as the recording device and employing human subjects with a variety of cardiac abnormalities. To record an ECG waveform, a differential recording between two points on the body are made. Traditionally each differential recording is referred to as a lead. Application of computers to the ECG for machine interpretation was one of the earliest uses of computers in medicine. Of primary interest in the computer-based systems was the replacement of the human reader and the elucidation of the standard waves and intervals. General instrumentation requirements for the ECG have been addressed by professional societies.
