Errors in ECG parameter estimation from standard leadsets

With the availability of low-cost, high-speed computers with (relatively) vast amounts of storage has come something of an explosion in the application of "quantitative electrocardiography." A search of the Medline medical reference database on the subject string "quantitative AND electrocardiography" reveals no less than 509 citations, suggesting that the term has gained widespread acceptance. However, while quantitative techniques are, in general, to be welcomed to clinical medicine and research, their use as a diagnostic or patient monitoring tool begs a careful examination of just what is being counted and how it is being linked to physiology. In this study, the authors focus on the use of standard electrocardiographic lead systems as the basis for quantitative patient evaluation and attempt to highlight some limitations in the ability to extract meaningful parameters with such a limited sampling of human thoracic electrical activity.