June 4, 2008 -- NEW YORK (Reuters Health), Jun 4 - Findings from a Swedish study indicate that children with a family history of hypertrophic cardiomyopathy (HCM) should be screened at an early age because risk of sudden death peaks early.
"Familial HCM often shows marked progression of hypertrophy during puberty, which is sometimes used as a justification for delaying family screening until after puberty," Dr. Ingegerd Ostman-Smith, of Queen Silvia Children's Hospital, Gothenburg, and colleagues write in the May issue of the European Heart Journal. They note that current guidelines recommend HCM screening after 12 to 15 years of age.
To establish the age range at highest risk, the researchers examined the risk of sudden death in all 150 subjects diagnosed with HCM before 19 years of age from six regional pediatric cardiology centers; 58% were male, and 38% had familial HCM.
A total of 56 deaths were recorded within the cohort, including 47 that occurred before 18.9 years of age. Overall, 39 deaths were sudden arrhythmia deaths. Of these, 31 occurred before 19 years of age.
The annual mortality rates averaged 7.2% between 9 and 13.9 years of age. After 16 years of age, the average mortality rate dropped to 1.7%. The proportion of sudden deaths was significantly higher in the 9- to 13.9-year age band compared with the over-16-year age band (p = 0.025, odds ratio 3.75). Trends for sudden death were similar in both familial and idiopathic HCM.
The investigators found that the risk for sudden death in girls peaked at 10 to 11 years of age. In boys, the risk peaked at 15 to 16 years of age.
Data from the Swedish national cause-of-death registry confirmed that the mortality rate from HCM is significantly higher in 8- to 16-year-olds (0.112 per 100,000 age-specific population) than in 17- to 30-year-olds (0.055 per 100,000 age-specific population).
The findings are "a strong argument for family screening to be carried out at an early age in families with HCM, and for preparticipation screening for inclusion in sporting activities being carried out much earlier than 15 years of age, for all children with a family history of heart muscle disease," Ostman-Smith and colleagues conclude.
"The misleading practice of averaging annual mortality ranges in HCM over pediatric age groups with significantly different mortality rates should be abandoned," they advise.
Eur Heart J 2008;29:1160-1167.
Last Updated: 2008-06-03 15:26:57 -0400 (Reuters Health)
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