A conceptual model of cardiac repolarization in normal conduction and in ventricular conduction defects

Interactions between ventricular excitation and repolarization were examined in 300 subjects with normal ventricular conduction and 210 subjects with ventricular conduction defects (VCD). Two conceptual models were considered as possible mechanism for the influence of excitation sequence on repolarization. The first model postulates that excitation transverse to fiber orientation produces reverse repolarization, while parallel excitation is required for concordant repolarization. The second model attempts to associate repolarization sequence with variations in diastolic stress profiles. The results indicate that the first concept seems plausible for repolarization in ventricular free walls but fails in septum. The second concept is not likely to he a prominent determinant of the repolarization sequence