New Algorithm Can Help Predict Sudden-Death Risk in Kids With Hypertrophic Cardiomyopathy

By David Douglas

August 27, 2019

NEW YORK (Reuters Health) - Researchers have developed a new model to predict the individualized risk of sudden cardiac death (SCD) in children with hypertrophic cardiomyopathy.

Although the risk of SCD in this population is higher than that in adults, guidelines on cardioverter defibrillator implantation are largely based on observational adult studies, according to researchers.

"Up until now, there have been no validated algorithms to identify those children at high risk of SCD," Dr. Juan P. Kaski of Great Ormond Street Hospital in London told Reuters Health by email.

Dr. Kaski and colleagues analyzed data from a retrospective, multicenter, longitudinal cohort study conducted between 1970 and 2017, including 1,024 children aged 16 years or younger with hypertrophic cardiomyopathy (HCM). The primary end point was a composite outcome of SCD or an equivalent event (aborted cardiac arrest, appropriate ICD therapy, or sustained ventricular tachycardia associated with hemodynamic compromise).

Over a median follow-up of 5.3 years, 89 patients (8.7%) died suddenly or had an equivalent event. Using this information, the team validated their prediction model, which was based on unexplained syncope, maximal left-ventricular wall thickness, left atrial diameter, left-ventricular outflow tract gradient, and nonsustained ventricular tachycardia.

Symptomatic status did not improve the performance of the model. The C statistic was 0.69 and the calibration slope was 0.98.

The team then went on to compare the observed and predicted risk of SCD at five years by risk groups. Based on this, in patients with five-year SCD risk of 6% or more, the researchers estimate that 10 cardioverter defibrillators would have to be implanted for each such patient saved.

"This international multicentre study represents the largest published paediatric HCM population and provides, for the first time, a personalised tool to identify children and teenagers with hypertrophic cardiomyopathy at high risk of sudden cardiac death who may benefit from implantation of an ICD," concluded Dr. Kaski.

In an accompanying editorial, Drs. Robert O. Bonow and Elizabeth M. McNally of Northwestern University Feinberg School of Medicine, in Chicago, point out, "The importance of a sudden death risk calculator for children with HCM is clear and is of great public health benefit, but this risk score should be viewed as a work in progress."

As Dr. Bonow told Reuters Health by email, the study "represents the first step in creating a risk score for children and adolescents with hypertrophic cardiomyopathy. It should stimulate further research to create fine-tuning using additional factors such as genetic profiles and magnetic resonance imaging characteristics."


JAMA Cardiol 2019.