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Back to Cardiovascular Diseases
Cardiac tamponade
Cardiac tamponade is a medical emergency condition where a large amount
of a fluid (e.g. pericardial effusion) accumulates in the pericardial
space in a relatively short time.
This may lead to an elevated intrapericardial pressure (>15 mm Hg),
which prevents proper filling of heart cavities. Instead
of reducing the filling of both ventricles equally, the septum of the
heart will bend into either the left or right ventricle. The end result
is hemodynamic compromise, low stroke volume and shock.
Causes
Cardiac tamponade can happen acutely, such as from a stab wound, from
surgery, or from the heart muscle rupturing. Heart rupture will usually
happen (though it is very uncommon) around the site of myocardial
infarction.
Chronic cardiac tamponade is a slower process, where up to
two litres of fluid can enter the pericardial space over a period of
time. The pericardium will stretch to accommodate the extra fluid
leading in turn to reduced ventricular filling.
Causes include:
- Malignancy: metastasis to the pericardium.
- Pericarditis: infections, radiation, connective tissue diseases,
uremia or idiopathic pericarditis.
- Trauma
- Post-coronary intervention
- Post-cardiovascular surgery
- Post-myocardial infarction (Dressler's syndrome)
Symptoms and signs
The signs and symptoms can appear very similar to congestive heart
failure, with dyspnea, cough, hypotension and tachycardia. There usually is a history of sudden onset attributable to
trauma, particularly in younger patients.
Examination of the patient may reveal pulsus paradoxus and distention of
the jugular veins. The jugular veins may show loss of the normal
y-descent. On auscaltation, the heart sounds may sound muffled on
auscultation as the accumulated fluid dampen the normal heart sounds
transmitted through the chest wall.
Diagnosis
1. EKG shows low QRS voltage or electrical alternans.
2. Chest x-ray shows cardiac enlargement with the characteristic "water
bottle" appearance in some cases.
3. Echocardiography is the investigation of choice, showing the effusion
and its hemodynamic consequences in terms of chamber dimensions.
4. Catheterization can be used to confirm the diagnosis and measure the
diastolic pressures.
Treatment
1. Immediate pericardiocentesis
Needle evacuation of the fluid and lowering of the pressure, and then
treatment of the underlying cause.
2. Volume expansion
Volume expansion in cases with shock, until pericardiocentesis can be
performed.
3. Pericardiectomy
Anterior and posterior pericardiectomy may be needed in cases that
reacculmate.
4. Percutaneous balloon pericardiotomy
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