The T wave as a marker of dispersion of ventricular repolarization in premature infants before and while on treatment with the I_Kr channel blocker cisapride

Abstract

The interval from the peak to the end of the T wave and the ratio of this value to the onset Q to T peak interval, represents regional dispersion of repolarization across the ventricular wall. This is a potentially useful clinical index in the assessment of arrhythmic risk in premature infants being treated by blockade of the I(Kr) channels.

The effects of droperidol and ondansetron on dispersion of myocardial repolarization in children

“…The validity and value of Tp‐e as a surface ECG correlate of TDR and as a predictor of torsadogenic risk continues to be hotly debated in the cardiac electrophysiology literature (18). Evidence to support its clinical utility comes from studies of adults and children with both congenital and acquired LQTS (19–24), where increases of 20–35 ms were observed. Our study had >99% power to detect a 25 ms change.…”

“…Two such drugs, droperidol and ondansetron, are highly effective anti‐emetics. Postoperative nausea and vomiting (PONV) are two of the most common morbidities resulting from anesthesia and surgery (14), cause considerable distress (15–17), and are a major cause of delayed discharge and unplanned admission after elective surgery, especially in children older than three years (18–22). The benefits of highly effective prophylaxis are widely regarded in the anesthesia community as outweighing the apparent extremely low risk of TdP.…”

The Safety of Modern Anesthesia for Children with Long QT Syndrome

“…17,18 The value of QTc as a reliable metric for assessing drug torsadogenicity has been questioned because QT prolongation is neither necessary nor sufficient for TdP. The electrophysiologic substrate for this arrhythmia is exaggerated transmural dispersion of repolarization, [19][20][21][22][23] which, some have suggested, can be measured on the surface electrocardiogram as the interval between the peak and end of the T wave (Tp-e). 24 Studies of sevoflurane 17 and propofol 18 in healthy children demonstrate no increase in Tp-e, suggesting that neither is torsadogenic, though sevoflurane markedly prolongs QTc, and generalization to children with known LQTS is speculative.…”

Arrhythmic risk biomarkers for the assessment of drug cardiotoxicity: from experiments to computer simulations

“…The score has also been shown to be a more sensitive measure of repolarization changes induced by an I K r -inhibiting compound (Lu 35-138) than the QT/QT c interval (Graff et al 2008). Changes in steady-state repolarization are also reflected in changes in time intervals, such as increased T p T e and T p T e /QT p (Benatar et al  2002; Liu  et al  2006; Thomsen et al 2006 a , b ; Gallacher et al 2007), which represents increased transmural dispersion of repolarization (Benatar  et al . 2002; Antzelevitch et al 2007) as mentioned previously.…”