[Lead systems in orthogonal electrocardiography]

The paper deals with evaluating quality of some orthogonal and pseudoorthogonal electrocardiographic lead systems as Frank lead system, signals derived from standard electrocardiographic leads by Levkov's transform and some signals of the standard 12 lead system that roughly fulfill condition of geometrical orthogonality. The signals of the lead systems were assessed by means of a mathematical criterion of two vector orthogonality which was originally proposed for purposes of electrocardiography and proved by Netusil. Experiments done with signals of the CSE database of short-time rest ECG records have revealed that the best ECG lead orthogonality has been found for signal sets of I-aVF-V2, and I-III-V2 leads, resp. Unfortunately nearly the worst results were obtained for the widely used Frank orthogonal lead system. It means that this lead system can lead (under some specific conditions) to missing diagnostically important information.