Aim
To compare risk algorithms (HCMRisk‐Kids, ECG Risk‐score) in hypertrophic cardiomyopathy (HCM) without syndrome association (ns‐HCM) and with Noonan‐like syndromes (RAS‐HCM).
Methods
A national paediatric HCM cohort (n = 151), presenting <19 years of age, mean follow‐up 13.3 years, from all Swedish centres of Paediatric Cardiology (presenting 1972–2015), with 41 RAS‐HCM patients (61% males), and 110 ns‐HCM patients (68% familial; 65% males). The end‐point was a composite of sudden cardiac death and resuscitated cardiac arrest (SCD/CA). Risk‐factors were studied with Cox‐hazard regression, and receiver operating characteristic curve analysis (C‐statistic).
Results
There were 33 SCD/CA, 27/110 in ns‐HCM and 6/41 in RAS‐HCM (p = 0.27). In ns‐HCM HCMRisk‐Kids ≥6% at diagnosis had C‐statistic of 0.69 for predicting SCD/CA during first 5 years of follow‐up and positive predictive value (PPV) of 22%. After 7 years of age (HCMRisk‐Kids7plus), C‐statistic was 0.76. ECG Risk‐score ≥6 at diagnosis had C‐statistic 0.87 and PPV of 31%. Independent risk factors for SCD/CA were HCMRisk‐Kids7plus score (p = 0.005) and ECG risk‐score (p < 0.001), whereas early beta‐blocker dose (p = 0.001) and myectomy (p = 0.004) reduced risk. The sum of HCMRisk‐Kids7yplus and ECG Risk‐score7yplus ≥14 best predicted SCD/CA within 5 years in ns‐HCM with C‐statistic of 0.90 [0.83–0.96], sensitivity 100% and PPV 38%.
Conclusion
Combining the ECG Risk‐score with HCMRisk‐Kids improves risk stratification in ns‐HCM and shows promise in RAS‐HCM.