Signalment: 11.5 years old, Male, Standard Poodle
Presenting Complaint: He presented for a routine recheck appointment. Thirteen months previously he was diagnosed as being in congestive heart failure (CHF) and twelve months ago he went into an atrial fibrillation rhythm.

Presenting History

Lateral view

DV view

Lateral View:
	Evidence of Chamber Enlargement learn more
		Left Ventricle: Yes    The heart is markedly too tall.
		Right Ventricle: Yes    The heart is more than 4 ICSs wide.
		Left Atrium: Yes    Marked left atrial enlargement.
		Right Atrium: Indeterminate    The right atrium cannot be assessed in this projection. However when it is enlarged, the right auricle is also enlarged and when present it will result in a loss of the cranial waist
		Left Auricle: Indeterminate    The left auricle cannot be assessed in this projection
		Right Auricle: No    The cranial waist is normal
	Abnormalities of Great Vessels learn more
		Aortic Dilation: No    There is no loss of the cranial waist
		Main Pulmonary Artery Dilation: No    There is no loss of the cranial waist
		Caudal Vena Caval Enlargement: No    The caudal vena cava is not larger than the descending aorta
	Pulmonary Venous Distention learn more: Yes    Close to the carina the vessels are difficult to see, however deep into the cranio ventral lung the vein is larger than the artery.
	Airway Changes learn more
		Peribronchial Pattern: Yes    The airway markings are particularly easy to find in the cranial lung
	Alveolar Changes learn more
		Air Bronchograms: No
		Cotton-like Densities: No
		Lobar Sign: No
	Pleural Effusion learn more
		Fissure Lines: No
		Leafing of Lung Lobes: No
	Pulmonary Edema learn more: Yes    Recall that this is a conclusion based on the constellation of findings of left atrial enlargement, pulmonary venous engorgement, and peribronchial changes
	Evidence of Heartworm Disease learn more: No
	Other Findings
		None
	Radiographic Diagnosis
		Generalized cardiomegaly with profound left atrial enlargement and pulmonary edema
	Description
		Based on just the lateral view causes for generalized cardiac enlargement can include pericardial effusion, dilated cardiomyopathy and chronic mitral valve disease. We have also observed generalized cardiac enlargement with severe tricuspid valve dysplasia and right atrial enlargement, with mitral valve dysplasia and mitral stenosis and with severe aortic valve insufficiency. This is a large breed dog, weighing 27 kgs. One might expect that dilated cardiomyopathy might be a more likely consideration. This case and the last several are intended to remind us of the frequent occurrence of chronic mitral valve disease in large breed dogs.

DV View:
	Evidence of Chamber Enlargement learn more
		Heart too Wide: Yes
		Left Ventricle: No    I would typically expect to see the apex of the heart well on the left side.
		Right Ventricle: No
		Left Atrium: Indeterminate    Usually this projection is poor to assess left atrial enlargement. However when the left atrium is enlarged its auricle is also enlarged and the enlarged left auricle will distort the silhouette in the 3 oclock position.
		Right Atrium: No
		Left Auricle: Yes    Marked left auricular enlargement
		Right Auricle: Indeterminate    It usually cannot be assessed in this projection
	Abnormalities of Great Vessels learn more
		Aortic Dilation: No
		Main Pulmonary Artery Dilation: No
		Caudal Vena Caval Enlargement: Indeterminate    The caudal cava is obscured.
	Pulmonary Venous Distention learn more: Yes
	Airway Changes learn more
		Peribronchial Pattern: No
	Alveolar Changes learn more
		Air Bronchograms: Yes
		Cotton-like Densities: No
		Lobar Sign: No
	Pleural Effusion learn more
		Fissure Lines: No
		Leafing of Lung Lobes: No
	Pulmonary Edema learn more: Yes    As per the comments of the lateral view
	Evidence of Heartworm Disease learn more: No
	Other Findings
		None
	Radiographic Diagnosis
		Cardiomegaly with left auricular enlargement and pulmonary edema
	Description
		This projection does not depict the typical globose cardiomegaly of pericardial effusion. However the other differentials for cardiomegaly listed for the lateral view are still open. This projection nicely demonstrates left auricular enlargement.

Clinical Diagnosis   Chronic mitral valve insufficiency

Comment   This case attempts to illustrate the inability of routine thoracic radiographs to discriminate among the various causes of cardiomegaly. Echocardiography has become essential to differentiate between these various etiologies. Establishing the etiology is relevant because it markedly affects prognosis and it may have an effect on management.