Published March 2021
Daniel Gergen, MD
Samantha King, MD
Expert review – pending
- Identify an enlarged cardiac silhouette and determine the cardiac chambers accounting for cardiomegaly on a CXR.
Plan to spend 5-10 minutes familiarizing yourself with the animations of the PowerPoint and the key findings of this chest X-ray.
Instructions: Present the image either by expanding the window (bottom right) in a browser or downloading the PowerPoint file (downloading is recommended. Have the image pulled up in presenter mode before learners look at the screen to avoid revealing the diagnosis. Ask a learner to provide an overall interpretation. Then advance through the animations to prompt learners with key questions and reveal the findings, diagnosis, and teaching points. You can go back to prior graphics and questions by using the back arrow or scrolling back on the mouse wheel.
Official CXR Read: The heart is markedly enlarged. No focal regions of consolidation are appreciated. No free air is noted below the diaphragm.
Diagnosis: Ebstein anomaly complicated by severe tricuspid regurgitation and right ventricular failure leading to right ventricular and right atrial enlargement.
- Ebstein anomaly is a congenital malformation of the tricuspid valve and right ventricle leading to various potential right-sided cardiac complications.
- An enlarged cardiac silhouette is defined as a cardiac silhouette that is greater than half of the internal thoracic diameter. The differential for an enlarged cardiac silhouette on chest radiograph includes cardiomegaly, pericardial effusion, and portable/AP film.
- An enlarged right heart border with smooth contours is due to enlargement of either the right atrium, right ventricle, or both structures.
- Compare the silhouette shown here to this case of left-atrial enlargement from severe mitral valve disease.
- The right ventricle is an anterior structure. The lateral view demonstrates loss of the retrosternal clear space, the area between the sternum and the right ventricle. Loss of the retrosternal clear space is due to right ventricular enlargement.
- Shown is the apical 4-chamber view from the patient’s echocardiography. This image demonstrates a significantly enlarged right ventricle as well as an enlarged right atrium.
Take Home Point
- Cardiomegaly on a PA CXR is defined by a cardiac silhouette greater than half the internal diameter of the thorax.
- Loss of the retrosternal clear space suggests enlargement of the most anterior cardiac structure, the right ventricle.
Goodman, L. R. (2019). Felson's Principles of Chest Roentgenology E-Book: A Programmed Text. Netherlands: Elsevier Health Sciences.