QRS planarity studies in the vectorcardiogram clinical and experimental studies.

Vectorcardiograms in 163 clinical subjects of normal and various abnormal conditions obtained by Frank lead system and in 17 dogs of experimental myocardial injury or intra-ventricular conduction disturbances by McFee-Parungao method were transformed by exchange of axes of co-ordinates by the method of McFee et al. The non-planarity index, from the axes of the transformed frontal plane, was significantly higher during myocardial injury and bundle branch blocks as well as from diffuse intra-myocardial conduction disturbances than during normal clinical cases and the control records in animal experiments. The non-planarity index was not increased in localized block of the conduction system in dogs. Therefore, results suggest that this index might be a useful parameter to assess these conditions.