The Risk of Death in Children with HCM

Children with hypertrophic cardiomyopathy (HCM) who have a history of previous cardiac events and of syncope — loss of consciousness caused by low blood pressure — are at a higher risk of sudden death, according to a new meta-analysis published online in Heart & Lung.

Investigators also found that ventricular tachycardia (VT) and left ventricular hypertrophy (LVH) were also risk factors for cardiac death, and ventricular outflow tract (LVOT) obstruction was a potential risk factor for sudden cardiac death in children with HCM.

Current treatment strategies are usually based on reported risk factors for sudden cardiac death in adults, and as a result, no consensus on the management of pediatric patients exists, the investigators wrote.

For this research, investigators conducted a systematic review and meta-analysis of previously conducted studies to evaluate factors associated with sudden cardiac or cardiac death in children with hypertrophic cardiomyopathy.

Investigators found 30 studies that met the inclusion criteria for this analysis, which was observational studies with patients who are 18 years of age or younger and diagnosed with HCM. Of these, the endpoint of sudden cardiac death was observed in 22 studies, and the endpoint of cardiac death occurred in 18 studies. Twenty-five cohort studies, four case-control studies, and one cross-sectional study were included in this study, with six articles as low-quality articles and 24 articles as high-quality.

The studies enrolled a total of 9,673 patients.

Investigators found that that their results confirm a retrospective study that children with a personal history of syncope was a risk factor for sudden cardiac death. That also found that children with LVH were at higher risk of sudden cardiac death than patients without.

They acknowledge a limitation of their research is that most of the studies included in this analysis were retrospective, observational and done at single institutions. They indicated more robust prospective research was need to explore the factors related to cardiac death in children with HCM.

Hypertrophic cardiomyopathy is a chronic disease in which excessive contraction of the heart muscle can lead to the development of debilitating symptoms and cardiac dysfunction.

In patients with hypertrophic cardiomyopathy, the heart muscle becomes abnormally thick, making it harder for the heart to pump blood. The thickened heart muscle can cause shortness of breath, chest pain, or problems in the heart’s electrical system, resulting in life-threatening arrhythmias or sudden death, according to the Mayo Clinic.

In obstructive disease, the thickened heart wall can block or reduce the flow of blood from the left ventricle to the aorta.

It’s estimated that 1 in every 500 people have hypertrophic cardiomyopathy, but a large percentage of patients are undiagnosed, says the American Heart Association. Of those diagnosed, two-thirds have the obstructive form of the disease.

Commonly prescribed medications include beta blockers, anti-arrhythmic medications, calcium channel blockers, and anticoagulants, all therapies used to treat other cardiac conditions and to manage the consequences of HCM. Currently, no medication is available to specifically treat hypertrophic cardiomyopathy.