J Thorac Cardiovasc Surg 1999;118:92-93
© 1999 Mosby, Inc.
SURGERY FOR CONGENITAL HEART DISEASE |
Commentary
J. Alex Haller, MD,
Baltimore, Md
 |
Introduction
|
|---|
This study may be the key to our understanding of the cardiopulmonary defects associated with severe pectus excavatum deformities! Although older children, and especially teenagers with severe pectus excavatum deformities, have reported improvement in exercise tolerance and decrease in fatiguability after operative correction, studies that have shown some improvement in cardiac output after repair have nevertheless failed to indicate exactly how this improvement can be explained. The authors of this study have used a new technology, echocardiographic calculation of ventricular volumes before and after pectus excavatum repair, and have shown significant increase in ventricular volumes and increase in cardiac output at rest. In particular, the right ventricular volume changes after pectus repair are critically important observations and probably explain the functional cardiac output improvement during exercise after pectus excavatum repair. Our group
1 has recently shown that there is improvement in cardiac output with exercise after repair in teenagers, but we could not define a good explanation other than to suggest that there might be distortion of the heart as a result of compression. This article gives dramatic evidence that there is indeed on-line compression of the right ventricle and presumably, therefore, a decrease in filling volume followed by a decrease in cardiac output at rest.
The next step, which may already be in progress, is to carry out the study with exercise before and after the operation. The clearest evidence of functional improvement is with exercise, not at rest, and therefore probably this would be a definitive study to corroborate the impact of the sunken sternum on the right ventricle.
The authors focused on the lack of correlation of the degree of elevation of the sternum with the improvement in filling volumes of the right ventricle. However, I think they lose sight of the fact that the so-called pectus index measurements that they used did not have third-dimensional components and, therefore, they may not be documenting or detecting the actual correlation.
The real message of this study and its importance do not lie in correlating sternal elevation with improvement in cardiac output but rather in the fact that the compression of the right ventricle is relieved by operative correction, and this is the explanation for improvement in cardiac output.
|
References
|
|---|
-
Quigley PM, Haller JA Jr, Jelus KL, Loughlin GM, Marcus CL. Cardiorespiratory function before and after corrective surgery in pectus excavatum. J Pediatr 1996;128:638-43. [Medline]
Top
Introduction
References