Abstract 11959: Left Atrial Size and Function in Children and Young Adults With Obstructive vs. Nonobstructive Hypertrophic Cardiomyopathy

Abstract

Introduction: Left atrial (LA) strain has been recently used to improve assessment of left atrial (LA) function. In adults with hypertrophic cardiomyopathy (HCM), increased LA size and decreased LA strain are associated with LVOT obstruction (LVOTO) and higher risk for adverse cardiovascular outcomes. Scant data exists on the association of LA strain and size in children with HCM, comparing those with and without obstruction. Methods: For this pilot study, all patients from an existing pediatric BCH stress echo HCM registry who had adequate echocardiographic images to assess both LA size and strain were consecutively enrolled and retrospectively reviewed. Post-processing LA size and strain (reservoir and conduit) were performed with use of Tomtec/Philips LV strain. Children with HCM were divided into 2 groups: those with resting LVOT gradients <30 mm Hg (no obstruction) versus ≥30 mm Hg (obstruction). LA size, strain and diastolic indices were compared for those with and without obstruction. Results: A total of 48 children (63% male, median age 13 yrs, range 6-23yrs) with HCM and analyzable images from the registry formed the cohort. Patient demographics, LA size and strain, and diastolic indices are summarized in Table 1. HCM children with LVOTO had larger LA size (apical 4-chamber (A4C) cross sectional area: p<0.001), lower LA conduit and reservoir strain (p<0.05 for all), and increased diastolic dysfunction (p<0.05 for all). Conclusions: Despite their younger age, children with obstructive HCM had larger LA size, lower LA reservoir and conduit strain, and increased diastolic dysfunction compared to children with nonobstructive HCM. Larger studies are needed with longer follow-up time to assess association of LA strain with cardiac events in children.