Repolarization dispersion in patients with systemic sclerosis.

Systemic sclerosis (SSc) is associated with increased cardiac morbidity and mortality. Whether some electrocardiographic markers of arrhythmias predispose to early cardiogenic death in SSc remains controversial. This study evaluated the occurrence of previously reported as well as unstudied markers of repolarization in patients with SSc and assessed their prognostic implications. A total of 21 patients with SSc and 31 unaffected controls were included in this prospective study. Electrocardiograms were conducted under strict standards. Repolarization and dispersion parameters and markers of late ventricular potentials were determined using designated computer software. Results of multiple beats were averaged. There were no significant differences between the SSc and control groups in average QT intervals, average corrected QT intervals, average QT interval dispersion (QTd), average QT corrected dispersion (QTcd), and QT dispersion ratio. However, average QT apex dispersion, average JT dispersion, average JT corrected dispersion, and Tpeak-Tend corrected were significantly higher in patients with SSc than in controls. Late ventricular potentials were not found in patients with SSc or in controls. Increased QTd and QTcd were recorded in 1 patient who experienced ventricular arrhythmia before inclusion in the study. None of the remaining patients with SSc or the controls developed arrhythmia during the 9-year follow-up. Abnormal repolarization parameters may be observed in patients with SSc. However, their prognostic significance with regard to increased risk for repolarization-associated ventricular arrhythmias and increased cardiac death could not be determined in this study. Our findings endorse additional studies on this matter.