Starting with an innocent murmur…

Hypertrophic cardiomyopathy (HCM) is the second most frequent type of cardiomyopathy in childhood following dilated cardiomyopathy. It has a better prognosis but carries a risk of sudden death. The most common causes are genetic, and there are specific syndromes that manifest with HCM. It usually involves myocardial mechanical abnormalities and a risk of arrhythmia. However, affected children are frequently asymptomatic and are evaluated for another reason, for example in the context of family screening or detection of some abnormality through diagnostic tests. The diagnosis is established through imaging and the treatment may involve implantation of a defibrillator.