The physiological basis of ST-T variations in the electrocardiogram: a review.

ST-T aberrations in the Negro involve both sexes, all age groups and all electrocardiogram (ECG) leads and are benign in the asymptomatic subject. This suggests that the variations have physiological basis and that alterations in the electrochemical processes occurring during repolarization would explain the ECG counterparts. While an isoelectric J-point suggests a temporal dissociation between phases 0 and 1 of the action potential, an elevated J-point suggests that phase 1 starts before the end of phase 0. If the current changes in phases 2 and 3 are the same, the ST-segment and T wave would form a continuum. It is suggested that in the Negro, the force producing repolarization overrides that producing slow depolarization during phases 2 and 3 and that the net result of the conflicting electrochemical processes accounts for the ST-T aberrations in the Negro race.