Prolonged Tp-e interval and Tp-e/QT correlates well with modified Rodnan skin severity score in patients with systemic sclerosis

Abstract

Background: Ventricular arrhythmias can be seen in systemic sclerosis (SSc) patients and are thought to be a result of fibrosis or ischemia of the ventricular myocardium. Tp-e interval and Tp-e/QT ratio are electrocardiographic (ECG) indices to predict ventricular tachyarrhythmia and cardiovascular mortality. We aimed to evaluate Tp-e interval and Tp-e/QT ratio in patients with SSc.

Methods: A total of 107 patients with SSc (mean age, 48.6 ± 14.0 years; 96 females) and 100 healthy controls (mean age, 49.4 ± 8.6 years; 90 females) were enrolled. The standard 12-lead ECG was recorded; QTc, Tp-e interval and Tp-e/QT ratio were measured. Modified Rodnan skin severity score (MR-SSS) calculated for all SSc patients.

Results: Tp-e interval (90.7 ± 23.8 ms vs. 84.0 ± 20.6 ms, p = 0.032) and Tp-e/QT ratio (0.20 ± 0.05 vs. 0.18 ± 0.04, p = 0.007, respectively) were significantly prolonged in SSc patients than in the control group. Pearson's correlation analyses revealed positive correlations of MR-SSS with QTc (r = 0.427, p = 0.001), Tp-e interval (r = 0.620, p = 0.001) and Tp-e/ /QT ratio (r = 0.615, p = 0.001). MR-SSS (b = 2.108, p = 0.001) and CRP (b = 2.273, p = 0.027) were found to be significant independent predictors of Tp-e interval. Similarly, MR-SSS (b = 0.004, p = 0.001) was only a significant independent predictor of Tp-e/QT ratio among patients with SSc.

Conclusions: The patients with SSc had a prolonged Tp-e interval and Tp-e/QT ratio compared with normal subjects. Furthermore, this prolongation was well correlated with clinical severity score among patients with SSc. Ventricular repolarization dispersion as a predictor of ventricular arrhythmias was found to be diminished in patients with SSc. Patients with SSc, particularly with higher MR-SSS, should be followed closely for adverse cardiovascular outcomes.

Keywords: Tp-e interval; Tp-e/QT ratio; systemic sclerosis.