A classification of ventricular ectopic beats.

To develop a classification of ventricular ectopic beats based on the QRS complex, the frontal and precordial QRS vectors were examined in ECGs from 71 patients. The data were first analyzed in planar coordinates to permit comparison with some previous classifications. Next, because the QRS vector is angular data, the data were transformed to spherical coordinates. Multivariate statistical methods were used. Cluster analysis aided in the separation of groups. Although at least four groups were suggested using planar coordinates, only three groupings were identified on spherical coordinates. A classification function was developed that permits assignments of ectopies into these three groups. It correctly classified 97.2% of cases. Thus, this study provides a quantitative method that significantly defines groups of ventricular ectopic beats.