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Comparison of cardiac function in surgically corrected and congenitally corrected transposition of the great arteries
R J Peterson1, R H Franch, W A Fajman
1Department of Surgery, Duke University Medical Center, Durham 27710.
Insights
Children with complete transposition of the great arteries after baffle surgery maintain cardiac output during exercise. However, their ventricular ejection fractions do not increase, and volumes are enlarged.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Disease
- Cardiac Physiology
Background:
- The long-term function of the right ventricle against systemic pressure after atrial baffle procedures in complete transposition of the great arteries (cTGA) is not well understood.
- Assessing ventricular adaptation to stress is crucial for managing patients with complex congenital heart conditions.
Purpose of the Study:
- To evaluate the capacity of the anatomic right ventricle to sustain normal function against systemic pressure in children after atrial baffle procedures for cTGA.
- To compare pulmonary and systemic ventricular function during exercise in surgically corrected cTGA patients, isolated congenitally corrected transposition of the great arteries (ccTGA) patients, and healthy controls.
Main Methods:
- First-pass radionuclide studies were used to measure pulmonary and systemic ventricular function in 11 children post-baffle surgery for cTGA, 8 patients with ccTGA, and 10 controls.
- Ventricular function was assessed at rest and during exercise.
Main Results:
- Cardiac index increased similarly during exercise across all groups.
- Ventricular volumes were significantly larger in both cTGA and ccTGA groups compared to controls.
- Pulmonary and systemic ventricular ejection fractions failed to increase with exercise in the cTGA group, unlike in the control and ccTGA groups.
Conclusions:
- While cardiac index is maintained during exercise post-baffle surgery for cTGA, the inability of pulmonary and systemic ventricular ejection fractions to increase suggests impaired ventricular-arterial coupling.
- Enlarged ventricular volumes are a persistent finding in these patients, indicating potential long-term ventricular remodeling.
- Further investigation is needed to understand the clinical implications of these functional limitations.
Abstract:
The capacity of the anatomic right ventricle to sustain normal function against systemic pressure long after atrial baffle procedures in patients with complete transposition of the great arteries remains unknown. Pulmonary and systemic ventricular function was measured by first-pass radionuclide studies in 11 children 7 +/- 3 years (+/- standard deviation) after baffle procedures. For comparison, similar measurements were made in eight patients with isolated congenitally corrected transposition of the great arteries and in 10 children in a control group. Exercise increased heart rate and cardiac index to similar levels in all three groups. Ventricular volumes were greater than control volumes in both groups with congenital heart disease. Exercise increased pulmonary ventricular ejection fraction in the control and congenitally corrected groups, but not in the surgically corrected group. Systemic ventricular ejection fraction increased during exercise in the control group, but remained unchanged in both transposition groups. These results show that cardiac index during exercise is maintained in patients after baffle procedures for complete transposition of the great arteries. However, pulmonary and systemic ventricular ejection fractions fail to increase with exercise, and ventricular volumes are markedly greater than normal.