[Diagnostic value of the system of Frank's orthogonal leads in inveterate myocardial infarct].

Comparison of data obtained in recording corrected orthogonal leads of the Frank system and 12 classical ECG leads in 118 patients with ischemic heart disease, among whom there were 76 patients with an old myocardial infarction, showed that corrected orthogonal leads may be used in mass population survey with the use of automatic diagnostic machines. It was established that the following ECG indices may be used in recording Frank's corrected orthogonal leads in the diagnosis of cicatricial myocardial changes: amplitude and duration of Q wave, the Q/R and R/S coefficients, the appearance of wave S in lead "Z". In an old myocardial infarction of posterior localization changes are recorded in lead "Y", in infarction of antero-septal localization changes are recorded in lead "Z" and to a lesser degree in lead "X"; in infarction of antero-lateral localization changes are recorded in lead "X" and to a lesser degree in lead "Z".