Which radiographic finding is commonly associated with congestive heart failure in dogs?

• A. Pulmonary edema
• B. Vascular congestion may be evident
• C. Cardiac enlargement (often left atrial)
• D. Pleural effusion

Answer: (C)

In dogs, the most consistent radiographic sign of congestive heart failure is enlargement of the heart, especially the left atrium. Chronic mitral valve disease causes volume overload that enlarges the left atrium, and this change is often evident on chest radiographs even before overt edema develops. The left atrial enlargement creates a characteristic, enlarged cardiac silhouette that reflects the heart’s increased filling pressures and volume load, signaling progression toward CHF. As failure advances, pulmonary edema and vascular congestion can appear, and pleural effusion may occur, but left atrial enlargement is the most reliable and common radiographic indicator of CHF in dogs.