Transmural dispersion of repolarization: a complementary index for cardiac inhomogeneity.

Abstract

We thank Dr Dogan and his team for his thoughtful comments and suggestions. The first comment to our study relates to the percentage of defective cQTD patients that was higher in our study as compared to previous studies.[1]–[3] We would like to point out that defective cQTD occurred in 40% while recovery of cQTD occurred in the majority of patients (60%). Also, the mean cQTD in the overall population significantly decreased after transcatheter aortic valve implantation (TAVI) (47 to 40 ms, P = 0.049). We do agree, however, that cQTD determination to assess ventricular inhomogeneity and arrhythmia risk suffers from (technical) measurement difficulties resulting in increased inter- and intra-observer variabilities and imperfect estimates of the true ventricular repolarization inhomogeneity. Therefore, a different methodological perspective such as measurement of T-peak to T-end wave dispersion should also be investigated in patients undergoing TAVI albeit that this method is also likely to suffer from measurement difficulties when assessing the end of the T wave (especially in lead V1, V2 or aVF). We agree that further research is indeed needed to investigate whether repolarization dispersion measurements correlate with sudden death and arrhythmia risk as suggested by Dogan et al. with methods that include or correct for the different electrical properties of the different myocardial cells.