Evidence for local cardiac effects in electrocardiograms from a large electrode array.

The sensitivity of an extensive electrocardiographic examination to local cardiac regions was evaluated by comparison with findings in vectorcardiographic leads. Evaluation consisted of comparing QRS areas during different ventricular activation patterns. The ratio of areas from the vector-cardiogram (VCG) and extensive electrode systems differed by 15 to 23 percent, suggesting at least this degree of local cardiac influence on the extensive examination.