Outcomes in Pediatric Hypertrophic Cardiomyopathy Patients with Reduced Systolic Ventricular Function

Purpose Our aim was to determine the transplant-free survival for pediatric hypertrophic cardiomyopathy (HCM) patients with decreased left ventricular (LV) systolic function and identify risk factors for change in function. Methods There were 177 patients (<18 years old) identified in our centre's Heart Failure Database diagnosed with HCM between January 1, 2001 and July 1, 2017. Patients with at least mildly reduced LV systolic function on quantitative and/or qualitative assessment were compared to those with normal function. Changes in ejection fraction (EF) over time for the entire HCM cohort were analyzed using a linear regression model adjusted for repeated measures and risk factors associated with change were identified. Results Reduced LV function was observed in 31 patients (17.5%) of which 19 (61%) were male and 22 (71%) had idiopathic HCM. Median age at diagnosis was 1.2 years (IQR 0.06-10.2) and at follow-up was 6.0 years (IQR 1.2-14.6). The 7-year transplant-free survival for patients with reduced systolic function was 41% (95% CI 30-52%) compared with 92% (95% CI 90-94%) for patients with normal function (p<.0001). Factors associated with a decline in EF were increased LV posterior wall thickness z-score and intensive care unit (ICU) admission. LV outflow tract obstruction was associated with an increase in EF (Table 1). Conclusion Pediatric HCM patients with reduced LV systolic function have a significantly worse transplant-free survival than those with normal LV function. The presence of increased LV posterior wall thickness or admission to the ICU are independent predictors of worsening LV function over time.