Scientific comparisons of the frequency, course and relationships of coronary and other cardiovascular diseases pose stringent requirements on medical procedure, not met in the traditional clinical process; these are a common language, unambiguously defined criteria, routine standard procedure, personnel training and quality control. The electrocardiogram (ECG) is an objective record of events relevant to myocardial infarction ischemia, hypertrophy and function. However, clinical interpretation synthesizes ECG deviations in unpredictable ways. A systematic approach described here results in reliable recognition and classification of ECG findings which are of general interest and validity. Technicians and clerical personnel have been trained to "read" conventional ECG tracings in a highly accurate and consistent manner. The Minnesota Code and Procedure, or a similar approach, is needed to process large numbers of ECGs from population studies and clinical trials which remain committed to conventional scalar tracings. The Minnesota Code is not directly applicable to present needs for hospital ECG coding. In contrast to considerations of clinical judgment, the manual aspects of ECG pattern recognition, measurement and coding for ECG studies in natural populations and in hospitals should ultimately be replaced by computer processing.
Bibliographical noteFunding Information:
At that early time in the development of cardiovascular epidemiology it was required to render the best in clinical procedure to the stringent need for systematic and objective comparisons. Many cherished clinical diagnostic methods failed in application under field conditions which involve simple, rapid collection of data relevant to the diseases of interest while giving high levels of reproducibility. The ECG was considered to be "Laboratory of Physiological Hygiene, University of Minnesota, Minneapolis, Minnesota 55455. Jf Reprints including the detailed Minnesota Code are available from the author. Some of the material reported here was collected under grants from the American Heart Association & the U.S. Public Health Service (HE 4697, HE 03088, HE 06314).