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Hyperinflation of the lungs in infants with large left-to-right shunts
R I Markowitz1, K M Johnson, E M Weinstein
1Department of Diagnostic Imaging, Yale University School of Medicine, New Haven, Connecticut 06510.
Insights
Infants with large heart defects often have breathing issues and larger lung volumes. However, lung and heart size did not correlate with the severity of the heart shunt in this study.
Area of Science:
- Pediatric Cardiology
- Thoracic Imaging
- Congenital Heart Disease
Background:
- Infants with large left-to-right shunts from ventricular septal defects and atrioventricular canal defects frequently exhibit respiratory symptoms.
- Radiographic findings include hyperinflation, cardiomegaly, and increased pulmonary vascularity, potentially due to airway compression and edema.
Purpose of the Study:
- To measure thoracic, cardiomediastinal, and lung volumes in infants with large left-to-right shunts.
- To investigate the correlation between these volumes and the degree of the left-to-right shunt.
Main Methods:
- Utilized an automated planimetric device for volume measurements.
- Compared volumes in patients with large shunts to normal controls.
- Correlated patient size-corrected volumes with shunt size determined by cardiac catheterization.
Main Results:
- All measured volumes (thoracic, cardiomediastinal, lung) were significantly increased in infants with large left-to-right shunts compared to controls.
- No significant correlation was found between cardiac or lung volumes and the estimated shunt size.
Conclusions:
- While infants with large shunts show increased thoracic and lung volumes, these measurements do not reliably predict shunt severity.
- Further research may explore other imaging or clinical parameters for better shunt assessment in this population.
Abstract:
Infants with significant left-to-right shunts due to ventricular septal defects and atrioventricular canal defects commonly present with respiratory symptoms, such as shortness of breath while feeding, tachypnea, and wheezing. Radiographs show hyperinflated lungs as well as cardiomegaly and increased vascularity. Enlarged vessels adjacent to small compressible airways as well as peribronchial interstitial edema may cause diffuse air trapping. In this study, using an automated planimetric device, we measured the total thoracic, cardiomediastinal, and lung volumes in a group of patients with large left-to-right shunts as well as in a group of normal controls and found that, as expected, all volumes were significantly increased in the abnormal group. We also tried to correlate these volumes (corrected for patient size) with the degree of left-to-right shunt and found that there was no significant correlation between the cardiac or lung volumes and shunt size as estimated by cardiac catheterization.