Global Longitudinal Strain and Biomarker Dynamics in Children With Acute Rheumatic Fever and Mitral Regurgitation: A 12-Month Prospective Study.

BACKGROUND: Acute rheumatic fever (ARF) remains a significant cause of acquired heart disease in children, particularly in developing countries. Although left ventricular systolic function is usually preserved, subclinical myocardial dysfunction may be present. Global longitudinal strain (GLS) is a sensitive parameter for detecting early myocardial impairment. OBJECTIVES: This study aimed to evaluate subclinical myocardial dysfunction in children with ARF-related carditis using GLS and other strain parameters and to assess its progression over a one-year follow-up period according to the severity of mitral regurgitation (MR). METHODS: A total of 30 children with ARF-related carditis and preserved systolic function were prospectively enrolled. Patients were divided into two subgroups based on MR severity: moderate MR (Group 1, n = 12) and mild MR (Group 2, n = 18). Conventional echocardiographic parameters and speckle-tracking-derived strain measures were assessed at diagnosis, six months, and 12 months. GLS values were compared with those of age- and sex-matched healthy controls (n = 52). RESULTS: At diagnosis, GLS was significantly lower in ARF patients than controls (-19.9 ± 2.86 vs. -22.6 ± 4.65; p = 0.02) and at six months (-20.4 ± 3.42 vs. -22.6 ± 4.65, p = 0.04). Although GLS improved in the mild MR subgroup (-21.9 ± 3.82 vs. -22.6 ± 4.65, p = 0.41), it remained significantly impaired in the moderate MR subgroup (-19.25 ± 3.32 vs. -22.6 ± 4.65, p < 0.01) at 12 months. In multivariable linear regression analysis, GLS was negatively correlated with the severity of valve regurgitation (r = -0.53, p = 0.02) and NT-proBNP (r = -0.62, p = 0.012). CONCLUSION: GLS and NT-proBNP are sensitive indicators of subclinical myocardial dysfunction in children with ARF-related carditis, especially in those with moderate MR. Longitudinal strain imaging may enhance early detection and guide long-term monitoring.