Echocardiography, MRI, and angiography show the large right atrium (Figs. 25.9, 25.10) and whether or not the appendage contains mural thrombi. During angiography there is often stasis of the contrast material because of the decrease in size of the right ventricle (Figs. 25.10, 25.11) and the tricuspid incompetence. Contrast has been reported within the atrium for as long as 12 seconds after injection. (Such stasis is clearly a factor in the etiology of the thrombi in the atrial appendages, a common finding in this disease.) The tricuspid ring is dilated and the papillary muscles are incorporated in the obliterated deformed apex, which contrasts with the hyperkinetic contracting outflow segment of the right ventricle. Since the right atrium and right ventricle are essentially one chamber, an elevated dip and plateau wave is obtained from both at manometry. Cine angiographic studies and echocardiography demonstrate that in some patients contractions of the outflow portion of the ventricles are normal; it is the inflow tracts which are restricted. In others the outflow tracts may be distended, but continue to function. There will be incompetence of the veins in the neck and the azygos vein. Occasionally the prevertebral plexus may be filled by reflux. When there is pericardial fluid, it can be recognized between the right lateral atrial border and the cardiac silhouette.

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Fig. 25.9 A-C. Angiography in right-sided EMF. A,B Dilatation of the right atrium with filling defects due to thrombi. C There is marked dilatation of the pulmonary conus and infundibulum.

Fig. 25.10 An aneurysmally dilated right atrium (RA) in a patient with right-sided EMF. By contrast, the right ventricle is largely obliterated except for its hyperkinetic outflow tract.

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Fig. 25.11 A,B Progressive obliteration of the apex of the right ventricle over 2 years. The 1959 angiogram was by direct right ventricular puncture, whereas that in 1961 was by right atrial injection. (Courtesy of The British Journal of Radiology 1965).