Long-term prognosis in children with hypertrophic cardiomyopathy: an analysis of 37 patients aged less than or equal to 14 years at diagnosis.

The relation of clinical, electrocardiographic, and hemodynamic findings at diagnosis to presenting features and prognosis of hypertrophic cardiomyopathy in childhood was evaluated in 37 consecutive patients below 14 years of age at time of diagnosis (24 males and 13 females, mean age 7 +/- 4 years). A left ventricular out-flow tract gradient (mean 42 +/- 27 mmHg) was detected at cardiac catheterization in 13 (35%) patients. Clinical, electrocardiographic, and hemodynamic features in patients with and without a pressure gradient were similar. Patients who had moderate to severe functional limitation had a higher incidence of syncopal episodes (p less than 0.001), lower ejection fraction (p less than 0.01), raised pulmonary artery pressure (p less than 0.001), and left ventricular end-diastolic pressure (p less than 0.01). During a follow-up of 9.2 +/- 5.1 years (range 2-18), 9 (24%) patients died suddenly (2 with a recorded left ventricular outflow tract gradient). Univariate analysis showed that reduced ejection fraction (p = 0.0001), syncopal episodes (p = 0.003), increased left ventricular end-diastolic pressure (p = 0.03), and severe dyspnea (p = 0.04) were associated with a poor prognosis. However, multivariate analysis revealed ejection fraction (p = 0.0001) and syncopal episodes (p = 0.0097) as independent predictors of survival. In conclusion, sudden cardiac death was common and was well predicted by the combination of left ventricular dysfunction and syncope at time of diagnosis.