The Practice of Electrocardiography

Electrocardiography is a mature discipline so familiar to both doctors and patients that it's hardly noticed one of those tests that have always been there like the white count and hemoglobin not something one has to think about much or question. To some extent this view is valid but it overlooks some important points. Like the white count and hemoglobin electrocardiograms are produced by technicians using mechanical devices that turn out numbers but there is a difference. The white count and hemoglobin are reported as single values to be interpreted by the doctor who knows the patient and ordered the test but the graph produced by an EKG machine represents millions of numbers displayed as XY plots a message written in a language different from one's own. It requires transla­ tion and this means that the translator must not only know the lan­ guage but also be able to assess the effects on it of the many factors that may have modified its meaning between origin and delivery. There is potential for harm to the patient as well as for help in every facet of the process and to lose sight of this to see the tracing as a single whole would be like seeing words as units without con­ sidering the letters that compose them. When we read we do recog­ nize whole words patterns but having learned the letters first revert to this base intuitively when we encounter a new word or one that is misspelled.