The Construction of Mean Spatial Vectors From Null Contours

Abstract
Experimental and theoretic evidence reveal substantial errors in the determination of mean heart vector orientations exclusively from null contours. Over the limited range of orientations studied, the mean heart vector angle determined by the perpendicular-plane construction departs by as much as 17 degrees from the true angle. These sizable construction errors, strongly dependent upon such factors as heart position and medium shape, are superimposed upon other errors inherent in the many assumptions made in electrocardiographic field analysis.