Presentation
Poor exercise tolerance.
Patient Data
PA and lateral chest x-rays demonstrate markedly enlarged cardiac silhouette. There is a double contour to the right heart border and splaying of the carina.
The aorta is somewhat ectatic. There are no overt features of congestive cardiac failure at this time.
Single image from a CT (obtained for unrelated reasons) at the level of the heart confirms cardiomegaly, with dilatation of all chambers (the left atrium most prominent). No pericardial effusion.
Contours - Splayed carina (red), and double contour. When correlated to the CT it is evident that the most lateral contour is due to the right atrium (blue) and the more medial contour due to the left atrium (orange).
Figure 1: annotated x-ray of this same patient
Cardiothoracic ratio is measured on a PA chest x-ray, and is the ratio of:
- maximal horizontal cardiac diameter
- maximal horizontal thoracic diameter (inner edge of ribs / edge of pleura)
Figure 2: A normal measurement should be less than 0.5.
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