Pediatric cardiomyopathy: The Australian experience

Population-based studies have provided insight into the natural history of adult cardiomyopathy (CM), but comparable information for affected children is lacking. All Australian children diagnosed with primary CM at age 0–10 years between 1.1.1987 and 12.31.1996 were enrolled in a longitudinal cohort study. A single cardiologist and pathologist reviewed all cardiac investigations and histopathological material, respectively. During the study period, the overall incidence of CM was 1.24/105 person–years at risk. Indigenous children had a higher incidence of DCM (relative risk 2.8) and a higher rate of presenting death (16.7% vs. 2.6%). The 5-year freedom from death or transplantation was 63% for children with DCM (n = 184), 83% for those with HCM (n = 80), 53% for those with left ventricular non-compaction (LVNC) (n = 29) and 38% for those with RCM (n = 8). In subjects with DCM, positive viral identification and/or lymphocytic myocarditis were found in 30/44 (68.2%) cases with available early histology and 8/9 cases presenting with sudden death. Risk factors for death/transplantation comprised presenting age > 5 years, familial DCM, lower initial fractional shortening Z score and failure to increase fractional shortening Z score during follow-up. In subjects with HCM, an underlying syndromal, genetic or metabolic condition was identified in 46 (57.5%) of subjects. Risk factors for death/transplantation included concentric LV hypertrophy, presenting age < 1 year, lower initial fractional shortening Z score and increasing LV posterior wall Z score. Lymphocytic myocarditis and LVNC are important causes of childhood CM. This population-based study identifies pediatric subjects at risk of adverse events.