Echocardiographic predictors of poor outcome in infants with hypertrophic cardiomyopathy.

Although hypertrophic cardiomyopathy (HC) is readily diagnosed by echocardiography in infants with isolated ventricular hypertrophy, echocardiographic predictors of outcome have not been described in this age group. To identify echocardiographic predictors of poor outcome of infants with HC, we reviewed medical records and echocardiograms of all 19 patients with HC aged <1 year seen at the University of California, San Francisco, from January 1981 through December 1995. Thickness of the ventricular septum and the left ventricular (LV) posterior wall, ventricular septum/LV posterior wall ratio, LV mass, LV volume, LV mass/volume ratio, LV ejection fraction, and right ventricular anterior wall thickness were measured. The median age at diagnosis was 1 day; 11 were boys and 8 were girls. Within 1 year after birth, 10 patients died: the other 9 patients have survived to > 12 months of age. At the initial postnatal examination, the Z value for LV posterior wall was larger (median, 5.2 vs 1.3, p <0.04) and, consequently, the ventricular septum/LV posterior wall ratio was lower (1.6 vs 2.3, p <0.04) in nonsurvivors than in survivors. In serial studies, the Z value for both the ventricular septum and the LV posterior wall thickness increased in nonsurvivors, but decreased in survivors. Nonsurvivors had intrinsic metabolic disease or Noonan syndrome. Survivors had classic HC or maternal diabetes. We conclude that, in infants with HC, early or progressive hypertrophy of the LV posterior wall is a predictor of poor outcome, regardless of associated disease.