Pathophysiology and Natural History Congenital Heart Disease

Congenital aortic stenosis in children is characterized by low left ventricular systolic wall stress allowing for supernormal ejection performance. In contrast, adults with acquired aortic stenosis have normal or excessive systolic wall stress resulting in either normal or subnormal ejection performance. In this study young children with congenital aortic stenosis, older children and adults with congenital aortic stenosis, and adults with acquired aortic stenosis were evaluated to test the hypothesis that the childhood pattern of low wall stress would convert to the adult pattern with advancing age. Left ventricular end systolic wall stress was lower in both congenital aortic stenosis groups when compared with that in age-matched normal subjects or adults with acquired aortic stenosis. Ejection fraction was higher in both groups of patients with congenital aortic stenosis than in age-matched controls. There was no tendency in the 16 patients with congenital aortic stenosis, some of whom were followed to the age of 33, for the congenital pattern of wall stress and ventricular performance to convert to the adult pattern. These results suggest that there is a fundamental difference in the hypertrophic response to a pressure overload present at birth compared with the response to one acquired later in life. Circulation 75, No. 5, 973-979, 1987. CHILDREN WITH congenital aortic stenosis have abnormal left ventricular systolic wall stress resulting in supernormal ejection performance.".2 Adults with acquired aortic stenosis have normal or subnormal ejection performance.3-' We hypothesized that if patients with congenital aortic stenosis were permitted to mature into adulthood without relief of the stenosis, the adult pattern of stress and ejection performance would develop. Therefore, we analyzed ventricular performance and cardiac mechanics in three groups of patients with aortic stenosis: young children with congenital aortic stenosis, older children and adults with congenital aortic stenosis, and adults with acquired aortic steFrom the Cardiology Division, Department of Medicine, South Carolina Children's Heart Center, and the Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston. Address for correspondence: Blase A. Carabello, M.D., Cardiology Division, 816CSB, Medical University of South Carolina, 171 Ashley Ave., Charleston, SC 29425. Received July 18, 1986; revision accepted Jan. 29, 1987. *Current address: Cardiology Division, University of Kentucky Medical Center, Lexington, KY 40536. nosis. If our hypothesis were correct, wall stress would increase with age in patients with congenital aortic stenosis and evolve into the pattern of acquired adult aortic stenosis. Methods Study patients. Twenty-three consecutive patients with pure aortic stenosis who met our criteria for study (described below) were age-matched with 23 normal subjects. Normal subjects were chosen randomly for study on the basis of age and without any prior knowledge of their hemodynamic and angiographic data. Six groups, including a total of 46 subjects, were studied and compared: group YCAS, young children with congenital aortic stenosis; group YNL, young age-matched normal children; group OCAS, older children and adults with congenital aortic stenosis; group ONL, older age-matched normal subjects; group AAS, adults with acquired aortic stenosis; and group ANL, adult age-matched normal subjects. Group YNL and seven of nine subjects in group ONL were chosen from those undergoing electrophysiologic testing for arrhythmias in our pediatric catheterization laboratory. Before electrophysiologic testing these patients underwent pressure measurement and ventriculography to rule out structural cardiac disease. Patients free of cardiac anatomic abnormalities were Vol. 75, No. 5, May 1987 973 by gest on M ay 3, 2017 http://ciajournals.org/ D ow nladed from