Computer-aided electrocardiography.

The three principal forms of medical electrocardiography are the standard 12 lead electrocardiogram (ECG), the exercise ECG and the long-term ambulatory ECG. The volume of use of the 12 lead ECG is 10 to 20 times greater than that of the exercise test or the ambulatory test, and it has received correspondingly more developmental and marketing attention. A great increase in the rate of adoption of computerized electrocardiography was brought about when large scale integration of computer hardware made it possible to place the entire computational package within a standard-sized ECG cart. Exercise ECG testing involves processing a data sample minutes in duration. Only a very few diagnostic possibilities are examined; emphasis is on measurements of the ST segment and on non-ECG observations. Ambulatory electrocardiography currently involves only one or two ECG leads and these are tested for only a few diagnostic possibilities; however, duration of the data sample is relatively long, usually 24 hours. Computer processing involves examination of about 100,000 cardiac cycles for RR interval, QRS shape and ST segment deviation.