The role of the electrocardiographic phenotype in risk stratification for sudden cardiac death in childhood hypertrophic cardiomyopathy
Gabrielle Norrish, Constantin‐Cristian Topriceanu, Qu Chen, Ella Field, Helen Walsh, Lidia Ziółkowska, Iacopo Olivotto, Silvia Passantino, Silvia Favilli, Aris Anastasakis, Vasiliki Vlagkouli, Robert G. Weintraub, Ingrid King, Elena Biagini, Luca Ragni, Terrence Prendiville, Sophie Duignan, Karen McLeod, Maria Ilina, Adrián Fernández, Regina Bökenkamp, Anwar Baban, Fabrizio Drago, Peter Kubuš, Piers E.F. Daubeney, Sian C. Chivers, Georgia Sarquella‐Brugada, Sergi César, Chiara Marrone, Constancio Medrano, Reyes Álvarez García-Rovés, Orhan Uzun, Ferrán Gran, Fernandez J Castro, Juan R. Gimeno, Roberto Barriales‐Villa, Fernando Moya Rueda, Satish Adwani, Jonathan Searle, Tara Bharucha, Ana Siles, Ana Usano, Torsten B. Rasmussen, Caroline B. Jones, Toru Kubo, Jens Mogensen, Zdenka Reinhardt, Elena Cervi, Perry Elliott, Rumana Omar, Juan Pablo Kaski
Abstract
AIMS: The 12-lead electrocardiogram (ECG) is routinely performed in children with hypertrophic cardiomyopathy (HCM). An ECG risk score has been suggested as a useful tool for risk stratification, but this has not been independently validated. This aim of this study was to describe the ECG phenotype of childhood HCM in a large, international, multi-centre cohort and investigate its role in risk prediction for arrhythmic events. METHODS AND RESULTS: Data from 356 childhood HCM patients with a mean age of 10.1 years (±4.5) were collected from a retrospective, multi-centre international cohort. Three hundred and forty-seven (97.5%) patients had ECG abnormalities at baseline, most commonly repolarization abnormalities (n = 277, 77.8%); left ventricular hypertrophy (n = 240, 67.7%); abnormal QRS axis (n = 126, 35.4%); or QT prolongation (n = 131, 36.8%). Over a median follow-up of 3.9 years (interquartile range 2.0-7.7), 25 (7%) had an arrhythmic event, with an overall annual event rate of 1.38 (95% CI 0.93-2.04). No ECG variables were associated with 5-year arrhythmic event on univariable or multivariable analysis. The ECG risk score threshold of >5 had modest discriminatory ability [C-index 0.60 (95% CI 0.484-0.715)], with corresponding negative and positive predictive values of 96.7% and 6.7. CONCLUSION: In a large, international, multi-centre cohort of childhood HCM, ECG abnormalities were common and varied. No ECG characteristic, either in isolation or combined in the previously described ECG risk score, was associated with 5-year sudden cardiac death risk. This suggests that the role of baseline ECG phenotype in improving risk stratification in childhood HCM is limited.