The Corrected Orthogonal Electrocardiogram

A NUMBER of reports on normal ranges of corrected orthogonal electrocardiographic measurements have appeared in the literature.'-12 They were derived, however, from limited numbers of subjects and the types of electrocardiographic and vectorcardiographic measurements varied largely from one study to another. The reported results are therefore not always strictly comparable. In spite of these limitations, a striking similarity in results was found, together with a significant decrease in size of normal ranges as compared to conventional vectorcardiographic systems. Both these features can be attributed to the lead corrections used, which reduce markedly interindividual variations in effective electrical lead direction and lead strength.'3 Data reported in the present study can, therefore, serve as standard for any of the corrected orthogonal lead systems.'4'7 Discrepancies in direction are negligible for all practical purposes, and amplitude values can be easily converted from one system to another by use of standard conversion factors.'8' 19 The Frank lead system15 used in the present study has been gaining widespread acceptance because of its ease of application. No general agreement exists on optimal electrocardiographic and vectorcardiographic