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Maturation of pulmonary input impedance spectrum in infants and children with ventricular septal defect
Insights
Pulmonary vascular disease in infants with ventricular septal defect (VSD) may be detected by analyzing the pulmonary input impedance spectrum. This analysis can help identify early signs of pulmonary damage in young children.
Area of Science:
- Pediatric Cardiology
- Pulmonary Hypertension
- Biomedical Engineering
Background:
- Ventricular septal defect (VSD) can lead to pulmonary vascular disease.
- Pulmonary input impedance spectrum analysis has shown promise in older children for detecting pulmonary vascular changes.
Purpose of the Study:
- To evaluate if the frequency of the impedance modulus minimum in the pulmonary input impedance spectrum can detect pulmonary vascular disease in infants with VSD.
- To compare impedance spectra between infants and older children with VSD.
Main Methods:
- Compared pulmonary input impedance spectra of 25 infants (≤2 years) with 20 children (2-7 years) with VSD.
- Subdivided groups by mean pulmonary artery pressure (moderate ≤35 mm Hg, high ≥40 mm Hg).
- Analyzed pulmonary vascular resistance, characteristic impedance, and frequency of the modulus minimum.
Main Results:
- Infants with moderate pulmonary artery pressure (Group 1A) showed higher pulmonary vascular resistance, characteristic impedance, and a different modulus minimum frequency compared to older children (Group 2A).
- Pulmonary vascular resistance and characteristic impedance decreased with age, correlating with body surface area.
- While pulmonary vascular resistance and impedance were similar in high-pressure groups (1B and 2B), only older children (Group 2B) showed evidence of pulmonary damage.
Conclusions:
- The frequency of the impedance modulus minimum may serve as an indicator for pulmonary vascular disease in infants with VSD.
- Age-related changes in pulmonary vascular mechanics influence impedance spectrum characteristics.
- Early detection of pulmonary vascular disease in infants with VSD is crucial, and impedance spectrum analysis shows potential.
Abstract:
To determine whether pulmonary vascular disease can be detected in infants with ventricular septal defect (VSD) by the presence of an increase in the frequency of the impedance modulus minimum of the pulmonary input impedance spectrum, as has been implied for older children, spectra of 25 infants (2 years or younger) (group 1) were compared with spectra of 20 children (ages 2 to 7 years) (group 2). Groups were subdivided according to mean pulmonary artery (PA) pressure: those with moderate pressure levels (35 mm Hg or less, groups 1A and 2A) and those with high pressure levels (at least 40 mm Hg, groups 1B and 2B). Pulmonary vascular resistance, characteristic impedance and frequency of the modulus minimum were significantly lower in group 2A than in group 1A. The decrease in pulmonary vascular resistance and characteristic impedance with increasing age was consistent with body surface area increases; however, the shift in frequency of the modulus minimum could be more easily related to a decrease in the pulse wave velocity than to a shift in the primary reflection site. Pulmonary vascular resistance, characteristic impedance and the frequency of the first modulus minimum were comparable in groups 1B and 2B; however, none of the patients in group 1B had evidence of pulmonary damage, whereas 3 of 4 group 2B patients had microscopically apparent pulmonary vascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)