Cardiac Tamponade - Diagnosis

1. Collect the detailed history

2. Do a complete physical examination, give importance to the symptoms of the patient

3. Lab Studies:

• Creatine kinase and isoenzymes: Levels are elevated in patients with myocardial infarction and cardiac trauma.

• Renal profile and CBC count with differential: These tests are useful in the diagnosis of uremia and certain infectious diseases associated with pericarditis.

• Coagulation panel: The prothrombin time and activated partial thromboplastin time are useful for determining bleeding risk during interventions, such as pericardial drainage, the placement of pericardial windows, or both.

• Antinuclear antibody assay, erythrocyte sedimentation rate, and rheumatoid factor: Although nonspecific, results from these tests may give clues to a connective tissue disease predisposing to the development of pericardial effusion.

• HIV testing: Approximately 24% of all pericardial effusions are reported to be associated with HIV infection.

• Purified protein derivative testing: This is used to diagnose tuberculosis, which is an important and not uncommon cause of pericardial effusion and tamponade.

4. Imaging studies

• Chest radiography findings may show cardiomegaly, water bottle–shaped heart, pericardial calcifications, or evidence of chest wall trauma

• Although echocardiography provides useful information, cardiac tamponade is a clinical diagnosis The following may be observed with 2-dimensional echocardiography:

• An echo-free space posterior and anterior to the left ventricle and behind the left atrium: After cardiac surgery, a localized posterior fluid collection without significant anterior effusion may occur and may readily compromise cardiac output.

• Early diastolic collapse of the right ventricular free wall

• Late diastolic compression/collapse of the right atrium

• Swinging of the heart in its sac

• LV pseudohypertrophy

• A greater than 40% relative inspiratory augmentation of right-side flow

• A greater than 25% relative decrease in inspiratory flow across the mitral valve

• Conditions that may simulate pericardial effusion on 2-dimensional echocardiography findings include the following:

• A large left pleural effusion

• Any tumor surrounding the heart

• Mitral annular calcification

• A descending thoracic aorta

• A catheter in the right ventricle

• An enlarged left atrium

• An annular subvalvular LV aneurysm

• A bronchogenic cyst

5. Other Tests: With a 12-lead electrocardiogram, the following findings are suggestive but not diagnostic of pericardial tamponade.

Sinus tachycardia

• Low-voltage QRS complexes

• Electrical alternans (also observed during supraventricular and ventricular tachycardia): Alternation of QRS complexes, usually in a 2:1 ratio, on electrocardiogram findings is called electrical alternans. This is due to movement of the heart in the pericardial space. Electrical alternans is also observed in patients with myocardial ischemia, acute pulmonary embolism, and tachyarrhythmias.

• PR segment depression

6. Procedures:

• Swan-Ganz catheterization

7. Histologic Findings: Occasionally, a pericardial biopsy is performed when the etiology of the pericardial effusion that caused the tamponade is unclear. This is especially useful in cases of tuberculous pericardial effusions because cultures of the pericardial fluid in these cases rarely yield a positive result for mycobacteria.

Category: Medicine Notes