Establishing Age-Specific and Sex-Specific Norms for Mitral Valve E-Point Septal Separation (EPSS) Measurements in Pediatric Patients

Objective: Pediatric heart failure is a rare condition with significant morbidity that requires timely diagnosis and treatment. Mitral valve E-point septal separation (EPSS) may be used as an estimate of systolic function in this evaluation. Although well studied in adults, there is limited literature looking at pediatric EPSS values. The goal of this study was to establish normal pediatric EPSS values that can serve as a reference in this evaluation. Methods: This was a single-center retrospective study of 455 pediatric patients aged 17 years or younger, who had an outpatient transthoracic echocardiogram performed from January 1, 2020, until June 26, 2023. Those with reduced ejection fraction and cardiac abnormalities were excluded. EPSS measurements were taken from parasternal long-axis B-mode views. Relationships between EPSS and patient biometric and echo measurements were evaluated. Consistency of EPSS measurement between independent reviewers was also evaluated. Results: Across all patients, the median EPSS for all measurements was 2.25 mm (IQR 2.06 mm). When looking specifically at the lowest 3 EPSS measurements for each patient, the median EPSS was 1.33 mm (IQR 2.56 mm). EPSS demonstrated statistically significant ( P <0.05) but low magnitude ( R <0.3) correlations with several patient biometric and echo measurements, including a negative correlation with ejection fraction and a positive correlation with age, height, weight, and body surface area. There was no significant correlation with sex. Interclass correlation by Cronbach Alpha was 0.951. Conclusions: EPSS measurements observed in this large pediatric patient sample are lower than those reported in both adults and children. Differences in imaging and measurement technique may explain these observed differences. Future prospective studies are needed to explore these differences and better define reference EPSS values and their clinical implications.