Characterisation and prognostic implications of the 12-lead electrocardiogram in children with RASopathy-associated hypertrophic cardiomyopathy

Background The 12-lead ECG is a simple, inexpensive clinical tool with a key role in the assessment of patients with hypertrophic cardiomyopathy (HCM). The aims of this single centre, retrospective cohort study were to characterise ECG findings and to identify potential ECG predictors of major adverse cardiovascular events (MACE—cardiovascular mortality, resuscitated cardiac arrest, ventricular arrhythmias with haemodynamic compromise, appropriate implantable cardioverter defibrillator therapy or heart failure hospitalisation) in children with RASopathy-associated HCM (RAS-HCM). Methods The resting 12-lead ECGs of 84 children with RAS-HCM were compared with those from 113 patients with sarcomeric HCM (s-HCM). Results A significant proportion of ECGs in RAS-HCM had superior axis deviation (29.8% vs 2.5%, p value<0.001) and voltage criteria for right ventricular hypertrophy (52.4% vs 28.3%, p value<0.001), and a significantly lower prevalence of pathological Q waves (27.4% vs 47.8%, p value<0.001). Over a median follow-up period of 6.8 years (3.1–9.7), 19 patients (22.6%) with RAS-HCM suffered an MACE. Right atrial enlargement and ST segment changes>2 mm correlated with MACE on univariate analysis, with the latter remaining significant after adjustment in a multivariate model (adjusted relative risk (RR) 2.33, 95% CI 1.12 to 4.86, p value 0.024). Conclusion These findings suggest that the 12-lead ECG may be a useful screening tool to distinguish RAS-HCM from s-HCM in everyday practice and could have potential implications for prediction of adverse outcomes.