Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Two The Thorax 135
Fig. 2-107 A 3-month-old female
Collie was brought in for evaluation
of a grade 5/6 holosystolic murmur.
The cardiac silhouette is of normal
size. A, On the lateral radiograph the
caudal margin of the cardiac silhouette
appears straight and there is a
bulge on the cranial dorsal margin
(arrows). B, On the ventrodorsal
radiograph a bulge is present in the
cranial mediastinum cranial to the
cardiac silhouette (arrows). The
radiographic findings are indicative
of aortic arch enlargement.
Diagnosis: Aortic stenosis.
A
B
HEART DISEASE AND CONGESTIVE HEART FAILURE
Heart disease in the form of a structural or functional heart abnormality may be present
for a long time before an animal develops congestive heart failure–related circulatory
inadequacy resulting in congestive changes in other organs. The presence of an enlarged
cardiac silhouette is not an indicator of heart failure. Rather, changes in extracardiac
structures are used to define congestive heart failure. These changes may be divided into
those associated with left heart failure and those associated with right heart failure.