“Inverted Pulmonary Valve,” a Rare Cause of Severe Pulmonary Stenosis

Abstract We describe three cases – two detected prenatally and one postnatally – in which the pulmonary valve exhibited abnormal chord-like attachments to the right ventricle. This produced paradoxical valve motion, characterized by closure in systole and opening in diastole, mimicking atrioventricular valve function (“inverted pulmonary valve”). On fetal echocardiography, both prenatal cases appeared to represent mild-to-moderate pulmonary stenosis, typically associated with favorable outcomes. However, the neonate deteriorated rapidly following ductal closure, confirming duct-dependent physiology. Urgent balloon pulmonary valvuloplasty was required, resulting in a good clinical recovery. This case series emphasizes that an inverted pulmonary valve, although rare, should be considered a red flag finding on prenatal echocardiography and managed in a tertiary care setting with readiness for immediate intervention.