Tpeak-Tend interval as an index of global dispersion of ventricular repolarization: evaluations using monophasic action potential mapping of the epi- and endocardium in swine.
The ECG interval from the peak to the end of the T wave (Tpeak-Tend) has been used as an index of transmural dispersion of ventricular repolarization (DVR). The correlation between the Tpeak-Tend interval and the global DVR, however, has not been well-evaluated.


METHODS
Monophasic action potentials (MAPs) were recorded from 51+/-10 epicardial and 64 +/- 9 endocardial sites in the left ventricles of 10 pigs, and from 41+/-4 epicardial and 53+/-2 endocardial sites in the right ventricles of 2 of the 10 pigs using the CARTO mapping system. The end of repolarization times over the epi- and endocardium were measured, and the end of repolarization dispersions over the epicardium (DVR-epi), over the endocardium (DVR-endo) and over both (DVR-total) were calculated. The QTpeak, QTend and Tpeak-Tend intervals as well as the QTpeak and QTend dispersions were obtained from the simultaneously recorded 12-lead ECG.


RESULTS
The maximal Tpeak-Tend intervals (57+/-7 ms) were consistent with the DVR-total (58+/-11 ms, p>0.05), and significantly correlated with the DVR-total (r=0.64, p<0.05). However, the mean Tpeak-Tend intervals (44+/-5 ms), and Tpeak-Tend intervals from lead II (41+/-6 ms) and V5 (43+/-5 ms) were all significantly smaller than and poorly correlated with the DVR-total, as were the QTpeak and QTend dispersions (15+/-2 ms vs. 21+/-4 ms).


CONCLUSIONS
The maximal Tpeak-Tend interval may be used as a noninvasive estimate for the global DVR, but not the QTpeak and QTend dispersions, nor the mean Tpeak-Tend interval and that from a single lead.
Xia
Yunlong
Y
Department of Cardiology, University Hospital, Lund, Sweden.
Liang
Yanchun
Y
Kongstad
Ole
O
Holm
Magnus
M
Olsson
Bertil
B
Yuan
Shiwen
S
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D018780:Body Surface Potential Mapping / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004699:Endocardium / Q000502:physiology*; D006305:Health Status Indicators; D006329:Heart Conduction System / Q000502:physiology*; D010496:Pericardium / Q000502:physiology*; D013552:Swine; D016276:Ventricular Function