Echocardiography is the pivotal investigation for confirming cardiac tamponade and planning aspiration. Electrocardiography and chest radiography provide additional findings.
Echocardiography
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Diagnostic role: Echocardiography can confirm the diagnosis.
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Procedural role: Echocardiography helps identify the optimum site for aspiration of pericardial fluid.
Electrocardiographic findings
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Underlying disease: The electrocardiogram may show features of pericarditis or acute myocardial infarction.
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Complex size: A large pericardial effusion is associated with small electrocardiographic complexes.
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Electrical alternans: The electrical axis changes with alternate beats because the heart swings from side to side in the pericardial fluid.
Chest radiography
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Cardiac silhouette: The chest X-ray can show an enlarged globular heart.
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Normal appearance: The chest X-ray can also look normal.