Left Atrium Myocardial Remodeling and Prognostic Marker Derived from CMR Feature Tracking in Pediatric Hypertrophic Cardiomyopathy.
BACKGROUND The left atrium is an early sensor of left ventricular (LV) dysfunction. The prognostic value of left atrial (LA) strain derived from CMR Feature-Tracking has been demonstrated in adult patients with hypertrophic cardiomyopathy (HCM); however, its significance in pediatric patients with HCM remains unknown. Our study aims to assess LA myocardial function using multi-parametric CMR and to explore the relationship between LA strains with adverse outcomes in pediatric patients with HCM. METHODS This retrospective study included pediatric patients with HCM who underwent CMR from January 2011 to December 2020. Strain parameters were assessed using CMR -FT analysis. Cox regression analysis was performed to assess the associations between variables and clinical outcomes which included sudden cardiac death (SCD) or equivalent events and heart failure-related events. RESULTS The cohort comprised 284 patients (median age, 15.0 years [interquartile range (IQR) 13.0-18.0]; 184 men) and 42 age- and sex-matched normal controls. Compare with normal controls, pediatric patients with HCM had impaired LA reservoir and conduit strains (all P<0.001), with no evidence of a difference in LA booster strain. After a median follow-up period of 62.8 months, a total of 41 (14.4%) patients reached composite outcomes. After adjusting clinical and imaging parameters in multivariable cox analysis, LA reservoir strain (HR: 0.95, 95% CI: 0.91-0.98, P = 0.007), and conduit strain (HR: 0.92, 95% CI: 0.87-0.97, P = 0.002) remained significantly independent predictors of composite outcomes, but not showed in booster strain. Adding LA reservoir strain or conduit strain in turn to the clinical and imaging model resulted in significant improvements in model performance for both composite outcomes and SCD events, respectively (all p < 0.001). CONCLUSION LA reservoir and conduit strains derived from CMR -FT were impaired in pediatric patients with HCM and showed important prognostic value for adverse clinical outcomes, providing incremental prognostic value when combined in a model with clinical and conventional risk factors.