Congenital Cardiac Anomalies Part 2
Part 2 of my review of congenital cardiac anomalies for radiology board exams.
Study Guide/Show Notes:
What are the 5 T’s of cyanotic congenital heart disease?
A mnemonic to help you remember common causes of cyanotic congenital heart diseases as the 5 T’s mnemonic, as follows:
Tetralogy of Fallot
Truncus arteriosus
Transposition of the great arteries
Total anomalous pulmonary venous return
Tricuspid valve anomalies
Cyanotic congenital heart disease can be divided based on conditions with increased versus decreased pulmonary vascularity. What are some cyanotic congenital heart conditions that present with increased pulmonary vascularity?
Cyanotic congenital heart disease entities that present with increased pulmonary vascularity include a large ventricular septal defect, several types of total anomalous pulmonary venous return, and several types of truncus arteriosus.
What are some congenital heart disease entities that present with decreased pulmonary vascularity?
Cyanotic congenital heart disease entities that present with decreased pulmonary vascularity include tetralogy of Fallot, Ebstein anomaly with coexisting atrial septal defect, and hypoplastic right heart syndrome.
What are classic features of an Ebstein anomaly?
Ebstein anomaly results from abnormal tricuspid valve development with tricuspid regurgitation that often presents with hydrops fetalis. Classic imaging features include marked right-sided heart enlargement with a very enlarged right atrium. A buzzword for the appearance of the heart is the “box-shaped” heart on a chest radiograph. I remembered this as the “reverse Nirvana” lesion when studying for boards given one the band’s hit songs “Heart Shaped Box” being the reverse of the “Box-Shaped Heart”. On cross-sectional imaging expect apical displacement of the septal and posterior leaflets of the tricuspid valve. You can use the mitral valve attachment as a surrogate for the expected normal position of the tricuspid valve which, in Ebstein anomaly, will be apically displaced in relation to the mitral valve. Note an association with maternal lithium use—and “Lithium” was also a hit Nirvana song—and association with trisomies 13 and 21 and Turner syndrome. Ebstein anomaly may coexist with other congenital cardiac anomalies.
What are key features of partial anomalous pulmonary venous return (PAPVR)?
The underlying abnormality of PAPVR is anomalous connections of some, but not all, pulmonary veins with the systemic circulation instead of the expected drainage of all pulmonary veins to the left atrium. Four common subtypes exist: supra-cardiac, cardiac, infracardiac and mixed. Supracardiac PAPVR has an association with persistent left superior vena cava. Cardiac PAPVR commonly sees pulmonary veins drain to the right atrium and/or coronary sinus. Infracardiac PAPVR can have drainage of pulmonary vein(s) to the portal vein, inferior vena cava or hepatic veins. PAPVR has a strong associated with atrial septal defects in nearly half of cases.
What are common features of Scimitar syndrome?
Scimitar syndrome is a form of PAPVR and is also known as hypogenetic lung syndrome. Scimitar syndrome involves an anomalous pulmonary vein (PAPVR) that drains a hypoplastic lung, most commonly connecting to the inferior vena cava, but also can be seen with anomalous drainage to the portal vein or right atrium. Adults with Scimitar syndrome are prone to repeated pulmonary infections and this may be a clinical presenting symptom provided to you on a multiple choice question stem. If presenting as an infant, heart failure is likely which may be an indication of coexisting congenital heart disease. If the right to left shunt is significant pulmonary hypertension can develop (the Eisenmenger phenomenon).
What is total anomalous pulmonary venous return (TAPVR)?
TAPVR results when all pulmonary veins have abnormal drainage versus PAPVR where only some of the pulmonary veins drain anonymously. TAPVR is a cyanotic congenital heart entity (one of the 5 T’s). In TAPVR, all of the pulmonary veins connect to a structure that will eventually drain into the right atrium and death will ensue unless there is a coexisting right to left shunt via either a large patent foramen ovale or atrial septal defect. As in PAPVR, there is supracardiac, cardiac, infracardiac, and mixed patterns of TAPVR. Supracardiac is most common. On imaging look for right heart enlargement due to the increased right heart blood flow with normal left atrial size.
What is the classic descriptor on chest radiograph of supracardiac TAPVR?
The snowman appearance on a frontal chest x-ray is characteristic of supracardiac TAPVR. The snowman appearance results from a dilated vertical vein, superior vena cava, and brachiocephalic vein on top—all of which form the snowman’s head, with the enlarged right atrium forming the body.
True or false? TAPVR is associated with asplenia?
True. TAPVR is associated with heterotaxy and asplenia.
