Signal-averaged body surface mapping demonstrates an overlap between ventricular depolarization and repolarization in normal subjects, indicating that evaluating terminal QRS waves using only dipolar theory is difficult.
Challenges dipolar QRS analysis in normals; leaves open body surface mapping's role in repolarization assessment.
To examine the relation between ventricular depolarization and repolarization, body surface isopotential maps at the end of the QRS complex were studied in 32 normal subjects using a signal-averaged body surface mapping system. The number of beats averaged was 96-154 (mean 126.2). In this study, there were 8 types of isopotential map patterns at the end of the QRS complex. Mean +/- SD of QRS duration, appearance time of repolarization, and disappearance time of depolarization were 82.0 +/- 8.7 msec, 71.8 +/- 10.5 msec, and 79.7 +/- 9.4 msec, respectively. Time duration of overlapping depolarization and repolarization was 8.6 +/- 6.4 msec. The early repolarization was widely distributed on the left anterior chest and the upper sternal region. These results demonstrated the difference between the appearance time of repolarization and the disappearance time of depolarization for each lead. We concluded that it is difficult to evaluate ECG waves in the terminal portion of the QRS complex with the dipolar theory only.
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Shibata et al. (1991) studied this question.
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