Factors associated with establishing a causal diagnosis for children with cardiomyopathy.
OBJECTIVE
The goal was to identify the clinical variables associated with establishing a cause of cardiomyopathy in children.


METHODS
The Pediatric Cardiomyopathy Registry contains clinical and causal testing information for 916 children who were diagnosed as having cardiomyopathy in North America between 1990 and 1995. Children with a causal diagnosis were compared with those without with respect to several demographic, clinical, and causal testing variables.


RESULTS
Cardiomyopathy was 1 of 4 types, hypertrophic (34.2%), dilated (53.8%), restrictive (3.2%), or other or mixed (8.9%). Only one third of cases had a known cause. Children with a known cause for hypertrophic cardiomyopathy were more likely to be female, to be relatively smaller, to present with congestive heart failure, and to have increased left ventricular posterior wall thickness without outflow tract obstruction. For dilated cardiomyopathy, a known cause was associated with older age, lower heart rate, smaller left ventricular dimensions, and greater shortening fraction. Family history of cardiomyopathy predicted a significantly higher rate of causal diagnoses for all cardiomyopathy types, whereas family histories of genetic syndromes and sudden death were also predictive of a cause for hypertrophic and dilated cardiomyopathies. For hypertrophic cardiomyopathy, only blood and urine testing was associated with a causal diagnosis, whereas both viral serologic testing or culture and endomyocardial biopsy were independent predictors of a causal diagnosis in dilated cardiomyopathy.


CONCLUSIONS
Certain patient characteristics, family history, echocardiographic findings, laboratory testing, and biopsy were associated significantly with establishing a cause of pediatric cardiomyopathy. Early endomyocardial biopsy should be considered strongly for children with dilated cardiomyopathy, for definitive diagnosis of viral myocarditis. Although not widely used, skeletal muscle biopsy may yield a cause for some patients with hypertrophic cardiomyopathy and for patients suspected of having a mitochondrial disorder.
Cox
Gerald F
GF
Division of Genetics, Department of Medicine, Children's Hospital, Boston, Massachusetts, USA.
Sleeper
Lynn A
LA
Lowe
April M
AM
Towbin
Jeffrey A
JA
Colan
Steven D
SD
Orav
E John
EJ
Lurie
Paul R
PR
Messere
Jane E
JE
Wilkinson
James D
JD
Lipshultz
Steven E
SE
D001706:Biopsy; D015984:Causality; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004452:Echocardiography; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008487:Medical History Taking; D018482:Muscle, Skeletal / Q000473:pathology; D009205:Myocarditis / Q000175:diagnosis* / Q000209:etiology*; D009206:Myocardium / Q000473:pathology; D011379:Prognosis; D012042:Registries / Q000706:statistics & numerical data; D012189:Retrospective Studies