Predictors of Long-Term Outcome in Children with Hypertrophic Cardiomyopathy

Abstract

To date limited data are available to predict the progression to end-stage heart failure (HF) with subsequent death (non-SCD), need for heart transplantation, or sudden cardiac death (SCD) in children with hypertrophic cardiomyopathy (HCM). We aimed to determine predictors of long-term outcome in children with HCM. A total of 112 children (median 14.1, IQR 7.8–16.6 years) were followed up for the median of 6.5 years for the development of morbidity and mortality, including arrhythmic and HF-related secondary end points. HF end point included HF-related death or heart transplant, and arrhythmic end point included resuscitated cardiac arrest, appropriate ICD discharge, or SCD. Overall, 23 (21 %) patients reached the pre-defined composite primary end point. At 10-year follow-up, the event-free survival rate was 76 %. Thirteen patients (12 %) reached the secondary arrhythmic end point, and 10 patients (9 %) reached the secondary HF end point. In multivariate model, prior cardiac arrest (r = 0.658), QTc dispersion (r = 0.262), and NSVT (r = 0.217) were independent predictors of the arrhythmic secondary end point, while HF (r = 0.440), LV posterior wall thickness (r = 0.258), LA size (r = 0.389), and decreased early transmitral flow velocity (r = 0.202) were all independent predictors of the secondary HF end point. There are differences in the risk factors for SCD and for HF-related death in childhood HCM. Only prior cardiac arrest, QTc dispersion, and NSVT predicted arrhythmic outcome in patients aged <18 years. LA size, LV posterior wall thickness, and decreased early transmitral flow velocity were strong independent predictors of HF-related events.

Risk factors for sudden cardiac death in childhood hypertrophic cardiomyopathy: A systematic review and meta-analysis

“…A significant association with SCD was shown in two univariate analyses (p<0.0001 19 , p=0.004 20 ), and one multivariable analysis (p<0.001 20 ). Kamp et al 18 described a small cohort of patients with previous ICD implantation in which a previous AE was not significant for SCD, however this study was underpowered to detect a difference.…”

“…Six studies evaluated the predictive value of NSVT detected during ambulatory electrocardiographic (ECG) monitoring for SCD 12,15,19,20 or CVD 17,22 . Two found a significant relationship between NSVT and SCD 12,15 , with a further study reporting non-significance of NSVT but significance for inducible VT during an electrophysiology study (EPS) 19 .…”

“…A family history (FHx) of sudden cardiac death (SCD) was evaluated as a risk factor in seven studies 12,[17][18][19][20]22,27 . Only one study reported a statistically significant association with SCD (HR 10.6, 95%CI 1.2-90.2, p=0.03) 18 .…”

“…Presentation in infancy (<1 year) was consistently associated with an increased risk of CVD, likely secondary to congestive cardiac failure 7,22,28 ; however, outside infancy, the majority of studies found no association between age and the risk of death 12,20,[22][23][24]27 .…”

“…Eight studies compared the risk of death in symptomatic and asymptomatic patients 12,17,20,21,24,[26][27][28] , however the definition of symptomatic patients was highly variable. The presence of symptoms of congestive cardiac failure at presentation was significant in predicting an increased risk of CVD in 3 out of 4 studies with this end-point 20,21,27 .…”