Noninvasive determination of exercise cardiac function following Fontan operation.
The purpose of this investigation was to define mechanisms which increase cardiac output during exercise in patients without a functioning right ventricle. Radionuclide studies were performed at rest and during upright bicycle exercise on 16 patients following Fontan procedures and compared to studies in 10 normal children. The mean cardiac index of patients following Fontan procedures was 5.2 +/- 2.0 L/min/m2 (standard deviation) at rest and increased to 9.4 +/- 3.5 L/min/m2 during exercise (p less than 0.0001). Exercise values were similar to those observed in normal children. The mechanisms utilized to achieve high cardiac output following Fontan procedures included an increase in heart rate. Mean systemic ventricular ejection fractions were significantly less than in normal children. The resting ventricular end-diastolic volume and stroke volume indices were above normal and remained constant during exercise to high heart rates. These data clearly document that a large exercise cardiac output can be achieved by patients without a functioning right ventricle.
D000293:Adolescent; D000328:Adult; D001021:Aortic Valve / Q000637:transplantation; D002302:Cardiac Output; D002648:Child; D002675:Child, Preschool; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006325:Heart Atria / Q000601:surgery; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D011651:Pulmonary Artery / Q000601:surgery; D011877:Radionuclide Imaging; D014261:Tricuspid Valve / Q000002:abnormalities* / Q000601:surgery