Pulmonary atresia with “intact ventricular septum” associated with a ventricular septal defect: an apparent paradox?

Abstract Background Pulmonary atresia with intact ventricular septum (PA-IVS) is a rare congenital heart defect including atresia of the pulmonary valve, varying degrees of right ventricle and tricuspid valve hypoplasia, and coronary anomalies, without communication at the ventricular level. However, the term intact ventricular septum is not always appropriate, as a ventricular septal defect (VSD) whilst rare can be associated. Methods To describe this unusual association, we reviewed the hospital files of all children diagnosed with PA-IVS in our institution between 1985 and 2023 and our collection of fetal heart specimens. We used a data extractor to identify patients with PA-IVS and associated VSD. Patients with severe Ebstein anomaly or tricuspid valve dysplasia and associated pulmonary atresia were excluded. Results The total cohort included 302 consecutive patients and 54 fetal heart specimens. Eight children (2.6% of the cohort) and 2 fetuses (3.7%) had PA-IVS with an associated VSD (5 central perimembranous, 4 muscular, 1 outlet). In the patient with an outlet VSD, cardiac autopsy revealed a hypoplastic but not malaligned outlet septum, without aortic overriding, excluding the diagnosis of tetralogy of Fallot with pulmonary atresia. Conclusion The association of the so-called “PA-IVS” with a VSD shows that terminology used to describe congenital heart diseases carries multiple insufficiencies. Along the same line, using the term pulmonary atresia with VSD does not embrace the complexity of defects associating atresia of the pulmonary valve with a communication at the ventricular level. The variety of location of the VSD in the setting of diminutive right ventricle and pulmonary atresia suggest that the presence of a VSD is not ontogenically linked to the right ventricular maldevelopment but an associated defect.