A correlative study of serum digoxin levels and electrocardiographic measurements.

The ST-segment appearance, PR interval, corrected QU time and T-wave amplitude from standard electrocardiograms of 70 patients were correlated with serum digoxin levels done on the same day. The absence of a digtalis effect on ST segments, upright T waves and PTQ scores (a combination function of PR, QT and T) of one or less, correlated well with the absence of "toxic" serum digoxin levels (greater than 1,8 ng/ml). PTQ scores showed a significant linear correlation with serum digoxin levels, and PTQ scores of more than 3,0 were in all instances associated with "toxic" serum digoxin levels. These observations merit futher investigation and could be useful in clinical situations.