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[Interventricular muscular defect in the atrioventricular canal]
1Dipartimento Medico-Chirurgico di Cardiologia Pediatrica, Ospedale Bambino Gesù, Roma.
Insights
Muscular ventricular septal defects are rarely associated with atrioventricular canal malformations. This study found these defects often occur with complete atrioventricular canal and aortic coarctation, especially in non-Down syndrome patients.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Congenital Heart Disease
Context:
- Atrioventricular canal (AVC) defects are common congenital heart malformations.
- Muscular ventricular septal defects (mVSD) are a less studied subtype.
- The association between AVC and mVSD requires further investigation.
Purpose:
- To investigate the occurrence and characteristics of muscular ventricular septal defects in patients with atrioventricular canal malformations.
- To determine the prevalence of mVSD in complete versus partial AVC forms.
- To identify associated cardiac anomalies and demographic factors, including Down syndrome.
Summary:
- A retrospective study analyzed 151 patients with AVC (95 complete, 56 partial), including 81 with Down syndrome.
- Four patients (2.6%) presented with muscular ventricular septal defects (5 defects total).
- All mVSD cases were associated with complete AVC, aortic coarctation, and often hypoplastic left ventricle; only 1 case was in a Down syndrome patient.
Impact:
- This study highlights the rare but significant association of muscular ventricular septal defects with complete atrioventricular canal and aortic coarctation.
- Findings suggest a potential unique etiology, possibly related to fetal hemodynamic mechanisms.
- The low incidence in Down syndrome patients warrants further research into specific genetic or developmental pathways.
Abstract:
The muscular ventricular septal defect associated with the atrioventricular canal is a malformation which has not yet been extensively studied. Between June 1982 and December 1989, 151 patients with atrioventricular canal underwent echocardiography and angiocardiography in our Department. Of these 95 (62.9%) had a complete form and 56 (37.1%) a partial. Among the 151 patients, 81 (53.6%) presented Down syndrome. We found 5 muscular ventricular septal defects in 4 patients; in 3 cases there was a single defect and in one case two defects. These defects were midmuscular in all patients and one patient also presented an apical defect. All 4 patients with muscular ventricular septal defect presented a complete atrioventricular canal and aortic coarctation; 3 out of 4 patients had a hypoplastic left ventricle with absence of Down syndrome. The muscular ventricular septal defect is a malformation which is rarely associated with atrioventricular canal (4/151 = 2.6%). In our experience, it was always associated with a complete form with aortic coarctation and was very rare in Down syndrome patients (1/81 = 1.2%). These findings may represent a peculiar association of anomalies which may be caused by fetal hemodynamic mechanisms.