Diagnosis

The diagnostic test of choice is echocardiography.

A presumptive diagnosis can be made with:

1. A large globose heart on radiography and
2. The Triad of jugular venous distention, muffled heart sounds, and weak arterial pulse detected on physical examination.
3. Radiology:

• A very large globose heart (loss of chamber contour)
• Pulmonary edema is very unusual
• Pleural effusions are common. When present these can markedly obscure the silhouette of the heart thus “hiding” the radiographic appearance of a globose heart.
• Pulmonary metastatic lesions may be present (HSA)
• In the cat with hypertrophic cardiomyopathy we have seen both pleural effusion and pericardial effusion

2. ECG may show:

• Low amplitude QRS complexes
• Electrical alternans
• Usually normal (sinus rhythm)
• Sinus tachycardia
• Ventricular premature beats are common

3. Blood Work may show:

• CBC evidence of hemangiosarcoma may be present (nucleated rbc, regeneration, schistocytes, with a fairly normal PCV)

4. Echocardiography:

• Pericardial effusion is readily detected
• A tumor present in the region of the right auricle, right atrium, or right ventricle in cases of hemangiosarcoma
• A tumor at the base of the aorta (heart base tumor) may be noted
• Cardiac tumors are easier to visualize while the effusion is still present

5. Other tests:

• Cytology of pericardial fluid.
  • This analysis has been shown to be of little value in distinguishing between idiopathic and neoplastic etiologies. However, the pericardial fluid analysis may reveal a septic etiology or the presence of chyle

• Pneumopericardiography:
  • At the time of centesis, a volume of carbon dioxide equal to 1/2 to 3/4 the volume of fluid removed from the pericardial sac is injected into the sac followed by both lateral radiographic views and a D/V and V/D view. This procedure has been useful to identify the presence of heart base tumors. The availability of cardiac ultrasound makes pneumopericardiography much less useful.