| Abstract: | Clinically overt hypertrophic cardiomyopathy is the most common cause of sudden unexpected death in childhood and has significantly higher sudden death mortality in the 8‐ to 16‐year age range than in the 17‐ to 30‐year age range. A combination of electrocardiographic risk factors (a limb‐lead ECG voltage sum >10 mV) and/or a septal wall thickness >190% of upper limit of normal for age (z‐score > 3.72) defines a paediatric high‐risk patient with great sensitivity. Syncope, blunted blood pressure response to exercise, non‐sustained ventricular tachycardia and a malignant family history are additional risk factors. Of the medical treatments used, only beta‐blocker therapy with lipophilic beta‐blockers (i.e. propranolol, metoprolol or bisoprolol) have been shown to significantly reduce risk of sudden death, with doses ≥6 mg/kg BW in propranolol equivalents giving around a tenfold reduction in risk. Disopyramide therapy is a very useful adjunct to beta‐blockers to improve prognosis in those patients that have dynamic outflow obstruction in spite of large doses of beta‐blocker, and its use in patients with hypertrophic cardiomyopathy is not associated with significant pro‐arrhythmia mortality. Calcium‐channel blockers increase the risk of heart failure‐associated death in hypertrophic cardiomyopathy (HCM) patients with severe generalized hypertrophy and should be avoided in such patients. Amiodarone does not protect against sudden death, and long‐term use in children usually has to be terminated because of side effects. Therapy with internal cardioverter defibrillator implantation has high paediatric morbidity, 27% incidence of inappropriate shocks, and does not absolutely protect against mortality but is indicated as secondary prevention or in very high‐risk patients. |
