Objectives: 

Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden unexpected death in childhood and among athletes. Success at attempting to prevent sudden arrhythmia death rests on firstly, identifying individuals at increased risk, and secondly on instituting therapeutic measures to decrease risk.

Methods and results: 

Separate cohort studies in both adults and children with HCM has identified several electrocardiographic features that correlates strongly with an increased risk for sudden death, both including features reflecting depolarisation such as deviation in QRS-axis (p=0.05) and QRS-amplitude sum (p<0.0001), as well as morphological features reflecting disturbed repolarisation such as ST-depression (p=0.001), precordial T-wave inversion (p<0.0001) and prolongation of QTc (p=0.003). An ECG-risk score based on scoring different features of the 12-lead ECG identifies adult HCM- patients at risk for sudden death with a sensitivity of 85% and a relative risk of 10.1 [95%CI 4.2–24.3;p<0.0001]], and childhood HCM- patients with a sensitivity of 96% and relative risk of 24.3 [3.5–169; p<0.0001], a positive predictive value of 40% [16–68] and a negative predictive value of 100% [89–100]. Of medical interventions the only treatment to show a significant reduction in sudden death is high- dose beta-blocker therapy with lipophilic beta- blockers (propranolol, metoprolol) which confers a significant survival benefit even in high-risk patients (p=0.003), with a dose-dependent effect on mortality. The optimal dose is 6 mg/kg body weight or above in propranolol equivalents.

Conclusion: 

The ECG-risk score is the hitherto most specific risk factor described and can be used to identify children and adolescents in need of intervention to prevent sudden death.