Analysis of the PQ interval is insufficient for evaluating atrial repolarization, highlighting the need for QRST cancellation algorithms during sinus rhythm.
The Ta wave has the opposite polarity, and the duration is generally two to three times that, of the P wave. Although the Ta peak may occasionally be located in the PQ interval during normal AV conduction, it is unlikely that enough information can be obtained from analysis of this segment to differentiate normal from abnormal atrial repolarization. Hence, an algorithm for QRST cancellation during sinus rhythm is needed to further improve analysis.
Holmqvist et al. (Thu,) studied this question.