Recognizing and treating pericardial disease - Veterinary Medicine
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Recognizing and treating pericardial disease
The clinical signs of pericardial disease are similar to those of other heart problems whose treatment may conflict with how we treat pericardial effusion. And if tamponade develops, it's a true emergency. Here is the information you need to capably handle these cases, including a step-by-step protocol to perform pericardiocentesis.



Electrocardiogram (ECG) findings can support a diagnosis if a marked volume of pericardial effusion is present, but ECG findings are not pathognomonic. Electrocardiographic findings consistent with a diagnosis of pericardial effusion include

1. Decreased R-wave amplitude (due to increased fluid insulation between the heart and surface electrodes)

2. Sinus tachycardia (with concurrent cardiac tamponade)

2. These lead II ECGs (25 mm/sec) from a dog show electrical alternans in the top image and a sinus rhythm without electrical alternans after pericardiocentesis in the bottom image. Note the reduction in heart rate after pericardiocentesis.
3. Electrical alternans, particularly when large volumes of effusion are present. This is the phenomenon in which the R-wave amplitude varies markedly in a beat-to-beat fashion (Figure 2).19 Electrical alternans, produced by swinging of the heart within the fluid-filled pericardial space, is usually only present with large effusions. It has been shown in an experimental model that electrical alternans is rate-dependent and is most likely to occur at relatively normal heart rates in dogs (90 to 144 beats/min).20

4. Ventricular complexes may also be present.

3 & 4. Lateral and dorsoventral thoracic radiographs from a dog with marked pericardial effusion. Note the large, round or globoid cardiac silhouette typical with large amounts of pericardial effusion.
With pericardial abnormalities such as peritoneopericardial diaphragmatic hernias, the ECG findings may be normal.

Thoracic radiographs

High-quality thoracic radiographs are invaluable for diagnosing pericardial effusion and usually demonstrate a globoid cardiac silhouette. The size of the cardiac silhouette will depend on the volume of effusion (Figures 3 & 4). Pericardial effusion can often be distinguished from dilated cardiomyopathy because the cardiac silhouette is rounder and more clearly demarcated. However, you must consider other possible differential diagnoses for a large, rounded cardiac silhouette, such as tricuspid dysplasia. Also, occasionally small effusions can lead to cardiac tamponade, yet the radiographic findings are ambiguous. Rarely, heart base tumors can be seen on radiographs; they may lead to tracheal deviation.


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