LAUSR

Dear editor, We read with great interest the article by Yayla et al. [1] entitled ’Tp-e interval and Tp-e/QT ratio before and after catheter ablation in patients with premature ventricular complexes (PVC)’ published in the Biomarkers in Medicine. The authors aimed to assess the assessment of Tp-e interval and Tp-e/QT ratio before and after radiofrequency ablation in patients with frequent PVCs. They reported that there was a significant correlation between Tp-e/QTc ratio and PVC burden in patients with frequent PVCs and Tp-e interval, Tp-e/QT and Tp-e/QTc ratios were decreased significantly as compared with baseline values after radiofrequency ablation procedure. Myocardial repolarization can be evaluated with QT interval (QT), corrected QT interval (QTc), QT dispersion (QTd) and transmural dispersion of repolarization (TDR) [2]. Tp-e interval, which is the interval between the peak and the end of the T wave on an ECG, is accepted as an index of TDR [2,3]. Tp-e interval, the Tp-e/QT ratio and Tp-e/QTc ratio are also used as an electrocardiographic index of ventricular arrhytmogenesis [3]. In one study conducted by Ilgenli et al., smoking was found to be associated with prolonged Tp-e interval, increased Tp-e/QT ratio and Tp-e/QTc ratio [4,5]. There were 17 patients (11.2%) with history of smoking in the study of Yayla et al. This number may have an impact on repolarization abnormalities which were not analyzed separately in the aforementioned study of Yayla et al. Besides, Gürdal et al. found that thyroid stimulating hormone had a significant positive correlation with Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio [6]. However, no data are provided in the current study of Yayla et al. regarding thyroid stimulating hormone levels. Additionally, in this study, although LVEF <50% and LVEF ≥50% groups did not have a preablation difference, there may be a decrease in the Tp-e interval, Tp-e/QT and Tp-e/QTc ratios due to the increase in LVEF after ablation that is not evaluated in the study. In conclusion, Tp-e interval, Tp-e/QT and Tp-e/QTc ratios are novel and relatively simply assessed markers of ventricular repolarization. However, in their analysis, authors seem to ignore some significant covariates that may have an impact on these parameters including Tp-e interval, Tp-e/QT and Tp-e/QTc ratios.