title: Clinical features and outcomes of childhood hypertrophic cardiomyopathy: results from a national population-based study.
abstract: BACKGROUND
  Population-based studies have provided insight into the natural history of adult hypertrophic cardiomyopathy, but comparable information for affected children is lacking.
  
  
  RESULTS
  All Australian children who presented with primary cardiomyopathy at 0 to 10 years of age between January 1, 1987, and December 31, 1996, were enrolled in a longitudinal cohort study. A single cardiologist reviewed serial cardiac investigations on each subject. A total of 80 subjects with hypertrophic cardiomyopathy were identified. An underlying syndromal, genetic, or metabolic condition was identified in 46 subjects (57.5%). There were no cases of sudden death at presentation. Left ventricular outflow tract obstruction was present in 32 subjects (40%); right ventricular outflow obstruction was present in 10 (12.5%). Freedom from death or transplantation was 83% (95% CI, 73 to 90) 5 years after presentation and 76% (95% CI, 62 to 86) 10 years after presentation. By proportional-hazards regression analysis, risk factors for death or transplantation included concentric left ventricular hypertrophy, age at presentation <1 year, lower initial fractional shortening Z score, and increasing left ventricular posterior wall thickness relative to body surface area. At the latest follow-up, 54 of 65 surviving subjects had no symptoms, and 46 were receiving no regular medication.
  
  
  CONCLUSIONS
  Syndromal, genetic, and metabolic causes predominate in children with hypertrophic cardiomyopathy. Ventricular outflow tract obstruction is common. The clinical status of long-term survivors is good. This population-based study identifies children with hypertrophic cardiomyopathy who are at risk of adverse events.
authors.affiliation: Department of Cardiology, Royal Children's Hospital, Melbourne, Australia.
authors.forename: Alan W
authors.initials: AW
authors.lastname: Nugent
authors.forename: Piers E F
authors.initials: PE
authors.lastname: Daubeney
authors.forename: Patty
authors.initials: P
authors.lastname: Chondros
authors.forename: John B
authors.initials: JB
authors.lastname: Carlin
authors.forename: Steven D
authors.initials: SD
authors.lastname: Colan
authors.forename: Michael
authors.initials: M
authors.lastname: Cheung
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Davis
authors.forename: C W
authors.initials: CW
authors.lastname: Chow
authors.forename: Robert G
authors.initials: RG
authors.lastname: Weintraub
mesh_terms: D001145:Arrhythmias, Cardiac / Q000209:etiology; D002312:Cardiomyopathy, Hypertrophic / Q000209:etiology* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D005260:Female; D016027:Heart Transplantation; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009634:Noonan Syndrome / Q000209:etiology; D014694:Ventricular Outflow Obstruction / Q000628:therapy