Association of Anti-TNF Therapy with Ventricular Repolarization Indices in Patients with Rheumatoid Arthritis: A Longitudinal Electrocardiographic Study

Background: Patients with rheumatoid arthritis (RA) have an increased risk of cardiovascular morbidity that cannot be fully explained by traditional cardiovascular risk factors alone. Chronic systemic inflammation has been implicated in myocardial electrical remodeling, yet the effect of anti-tumor necrosis factor (anti-TNF) therapy on ventricular repolarization remains insufficiently characterized. This study investigated longitudinal changes in electrocardiographic markers of ventricular repolarization following anti-TNF therapy in patients with RA. Methods: This retrospective longitudinal study included 115 patients with RA who initiated anti-TNF therapy and had clinical, laboratory, and 12-lead electrocardiographic assessments at baseline and after approximately 24 weeks. Ventricular repolarization was evaluated using QT, corrected QT (QTc), Tpeak–Tend (Tp-e), corrected Tp-e (cTp-e), and Tp-e/QT. Cross-sectional associations between repolarization indices and inflammatory/disease-related variables were assessed at 24 weeks, together with longitudinal correlations between changes in these variables and changes in repolarization indices. Results: The mean age was 54.4 ± 12.2 years, and 81.7% of participants were women. After 24 weeks of treatment, significant reductions were observed in CRP, ESR, DAS28-CRP, and HAQ scores (all p < 0.001). The Tp-e interval decreased from 85.1 ± 13.6 to 75.3 ± 13.5 ms, and the Tp-e/QT ratio decreased from 0.20 ± 0.04 to 0.18 ± 0.03 (both p < 0.001), with moderate within-subject effect sizes for both changes (Cohen’s dz = 0.46). At 24 weeks, Tp-e and Tp-e/QT were positively correlated with inflammatory markers, disease activity, functional impairment, and disease duration. However, longitudinal change-to-change analyses showed no consistent associations between changes in inflammatory/disease activity measures and changes in repolarization indices, except for a weak correlation between ΔDAS28-CRP and ΔTp-e (r = 0.201, p = 0.031). Despite a significant reduction in mean QTc, the proportion of patients with prolonged QTc remained unchanged (18.3% at both assessments; McNemar p = 1.00). Conclusions: Anti-TNF therapy in patients with RA was associated with significant improvements in several ECG-derived ventricular repolarization indices alongside reductions in inflammatory and disease activity. However, the lack of consistent longitudinal correlations and the unchanged prevalence of prolonged QTc indicate that these findings should be interpreted as treatment-associated changes rather than evidence of a direct electrophysiological or antiarrhythmic effect of TNF inhibition. Prospective controlled studies incorporating clinical cardiovascular outcomes are warranted.