Cardiac Function in Pediatric Nephrotic Syndrome: Tissue Doppler Echocardiography

Background: Nephrotic syndrome (NS) is a common pediatric glomerular disorder traditionally considered renal-limited. Nonetheless, growing evidence suggests systemic implications, including subclinical cardiovascular involvement. This study aimed to evaluate early myocardial dysfunction in children with idiopathic NS using Doppler tissue echocardiography (DTE). Methods: In a case-control study, 87 children with idiopathic NS and 87 age- and sex-matched healthy controls were enrolled between 2021 and 2023 at Ali Asghar Pediatric Hospital in Zahedan, Iran. All participants underwent comprehensive DTE from apical four-chamber views to assess systolic and diastolic function. Key parameters included S′, E′, and A′ velocities; isovolumetric contraction time (ICT); isovolumetric relaxation time (IRT); ejection time (ET); myocardial performance index (MPI); and E/E′ and A/A′ ratios. Laboratory data and treatment response were also analyzed. Data were analyzed using SPSS version 26, with a significance level set at 0.05. Results: Children with NS demonstrated significantly reduced S′, E′, and A′ velocities; prolonged left ventricular IRT; shortened ICT and ET; and elevated MPI values, indicating early biventricular dysfunction. The right ventricular E/E′ ratio was significantly lower in treatment responders, suggesting improved diastolic function. MPI and timing parameters showed strong correlations with renal and metabolic markers, including blood urea nitrogen, serum albumin, and lipid levels. Conclusions: DTE-derived MPI serves as a valuable noninvasive marker for the early detection of subclinical cardiac dysfunction in pediatric NS. Incorporating MPI into routine cardiac assessments may improve risk stratification and guide therapeutic monitoring in this population.