Information loss in limb-lead electrocardiograms compared with twelve-lead tracings in a population survey among the elderly.

A total of 235 telve-lead electrocardiogram tracings representing all those traces with positive Minnesota codings from a population sample of persons aged 65 and over were re-coded on the basis of the six limb-leads alone. The over-all loss of information amounted to about 22.3 per cent of major abnormalities, as defined, but was higher than 50 per cent for some individual abnormalities such as abnormal Q and QS waves. Possible implications of these findings are discussed.