Z-score transformation of T-wave Morphology values to a standardized scale

Drugs that prolong the QTc interval to clinically relevant magnitudes are likely to be proarrhythmic if they also produce relevant changes in the morphology of repolarization waveforms. Concurrent analyses of QTc and the T-wave Morphology Combination Score (MCS) have already shown how this approach can improve characterization of repolarization effects for a number of drugs. In this study we develop a transformation of MCS values to standardized T-wave Morphology scores (TWM) which have the important advantage of being directly comparable to QTc. We then examined the relative merits of assessing changes in TWM values in addition to QTcF for 37 schizophrenia subjects exposed to Sertindole, a drug which is not considered acceptably safe as a broad treatment of schizophrenia.