Evaluation of ventricular repolarization in dermatomyositis and relationship with inflammation and autoimmunity

Dermatomyositis (DM) is a chronic multi-systemic inflammatory disorder of autoimmune origin, which has been associated with cardiovascular complications, including ventricular arrhythmias and sudden cardiac death. The Tp-e interval and Tp-e/QT ratio have been accepted as new markers for the assessment of myocardial repolarization and ventricular arrhythmogenesis. The aim of this study was to evaluate ventricular repolarization by using Tp-e interval and Tp-e/QT ratio in patients with DM, and to assess the relation with inflammation and autoimmunity. This study included 281 DM patients (180 females, 101 males; mean age 52.73 ± 15.80 years) and 281 control subjects (180 females, 101 males; mean age 53.38 ± 15.72 years). QTc, Tp-e interval and Tp-e/QT ratio were measured from the 12-lead ECG. The plasma level of blood routine test, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) was measured. These parameters were compared between groups. No statistically significant difference was found between two groups in terms of basic characteristics. In electrocardiographic parameters analysis, QTc, Tp-e interval and Tp-e/QT ratio were significantly increased in DM patients compared to the control group (441.44 ± 26.62 ms vs 422.72 ± 11.7 ms, 104.16 ± 24.34 ms vs 77.23 ± 16.25 ms and 0.27 ± 0.06 ms vs 0.20 ± 0.04 ms, all P value < 0.01). QTc, Tp-e interval and Tp-e/QT were positively correlated with NLR, CRP, and ESR (all P values < 0.01), and were increased in anti-Ro/SSA-52kD positive patients compared to those negative (452.33 ± 24.89 ms vs 438.55 ± 26.37 ms, 114.05 ± 22.68 ms vs 101.53 ± 24.13 ms, and 0.29 ± 0.06 ms vs 0.27 ± 0.05 ms, all P value < 0.01). Our study demonstrated that QTc, Tp-e interval, and Tp-e/QT ratio were increased in DM patients and were associated with inflammatory markers and anti-Ro/SSA-52kD positivity.