In 1957, Dr. N.J. Holt, a U.S. science doctor, invented the dynamic electrocardiogram that can trace the electrocardiogram under the condition of human activity and can be carried around. The machine is mainly used for clinical measurement of coronary artery disease, hypertrophic cardiomyopathy, class II valve prolapse and long Q-T syndrome patients with or without serious arrhythmia episodes, can be monitored suffering from intermittent arrhythmia, unexplained syncope and sick sinus node syndrome patient's condition, to understand the installation of pacemakers installed in the patient's body's functional status, to determine the efficacy of arrhythmia medication, observation of physical activity effect on the heart rhythm and blood supply to the heart. An ambulatory electrocardiograph consists of two parts. The first is a cassette or reel-to-reel tape recorder that can be carried around and records the ECG 24 hours a day, indicating the time of day on the chart and marking the patient's symptoms. The second is an analyzer that can play back the images from the tape at 30x to 120x real time, identify abnormal graphs on demand either manually or by a computer in the analyzer, and calculate and summarize the frequency of episodes of various abnormal rhythms over a 24- or 48-hour period.
In 1952, P. H. Langner developed the high-frequency electrocardiogram. He increased the frequency of ordinary electrocardiogram to 800Hz~3000Hz, the scanning speed was accelerated to 200mm/s~500mm/s, the magnification of electrocardiogram was increased to 1mV=50mm~100mm, and the high-frequency part which was filtered out by ordinary electrocardiogram was also detected.
The rapid development of electronic computer technology has promoted the application of computers in medical engineering. 1957, Pipberger, the former president of the American Heart Association, began to explore the use of computers for automatic analysis of electrocardiograms. 1962, the development of automatic analysis program for conventional 12-lead electrocardiograms was successful. Since then, organizations such as the World Health Organization, the International Heart Association, and the International Society of Electrocardiography have recommended the simultaneous recording of 12-lead ECGs as the basis for the development of electrocardiographs with which normal values and new diagnostic criteria can be established. Research into automated computer analysis of the electrocardiogram has been a great success worldwide, and the results of this research have accelerated the process of commercialization and clinical applications are becoming increasingly common.
There are roughly three types of automatic ECG analysis systems: the first is the establishment of specialized institutions that use large and medium-sized computers to automatically analyze and process the ECG and transmit the results via telephone lines to terminal equipment in each medical institution. The second type is the establishment of an ECG processing system using small and micro computers centered on medical institutions. The third type is a portable or hand-push type ECG machine with a built-in ECG automatic analyzing device. In addition, many ECG automatic analyzing systems have added some clinical practical functions, such as automatic writing and printing of ECG reports, automatic storage and reproduction of ECG.
Computer analysis of electrocardiogram facilitates mass storage of electrocardiogram data and retrieval of related information, which is especially suitable for cardiovascular disease screening and epidemiological studies. And it can significantly improve work efficiency. At the same time, it is conducive to the unification of measurement standards and the reduction of errors caused by manual reading of electrocardiograms. By converting ECG analog signals into digital signals, ECG can be classified correctly in a quantitative way, thus ensuring the accuracy of ECG interpretation. However, at present, because this technology is not yet perfect, it is still necessary to combine the automatic computerized interpretation of ECG and manual interpretation to explain various lesions in clinical practice. In short, computer analysis of electrocardiography is an emerging fringe discipline, the development of computer technology will certainly promote the development of electrocardiography.