Page 71 - Medicine and Surgery

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Chapter 2: Disorders of pericardium, myocardium and endocardium 67

surgical removal of a substantial proportion of the peri- ment, but follow-up observation is mandatory to iden-
cardium (pericardectomy). This is also helpful diagnos- tify developing tamponade. Pericardiocentesis (needle
tically, particularly for tuberculosis. aspiration of the fluid) may be indicated to establish the
cause and to relieve tamponade. In cases of recurrent
Prognosis effusion, surgical treatment with a pericardial window
The majority of patients respond well to surgery. The ex- allows drainage to the pleural space.
ceptions are if there is coexistent atrial fibrillation, valve
disease or left ventricular dysfunction.
Cardiac tamponade
Definition
Pericardial effusion Pericardial/cardiac tamponade is an acute condition in
which fluid in the pericardial sac causes impaired ven-
Definition
tricular filling.
Apericardial effusion is fluid in the pericardial sac.
Aetiology
Aetiology
The commonest cause of tamponade is malignancy. It
Almostanycauseofacutepericarditisinducestheforma-
may occur with other causes of pericarditis and effusion
tion of an exudate. A pericardial transudate may occur
and also as a post-traumatic complication following car-
as a result of cardiac failure.
diac catheterisation, cardiac perforation, cardiac surgery
or chest injury.
Pathophysiology
Fluid accumulating within the closed pericardium may
reduce ventricular filling and hence cause compromise Pathophysiology
of the cardiac output (cardiac tamponade). The pericardium is a non-distensible bag around the
heart. Once the space between the pericardium and the
heart becomes full of fluid the ventricles are prevented
Clinical features
from filling properly during diastole thus reducing the
Heart sounds are soft and apex beat is difficult to pal-
cardiac output.
pate. If the effusion accumulates quickly, features of low
cardiac output failure usually appear. Slow accumula-
tion of fluid is often well tolerated until very large due to Clinical features
distension of the pericardial sac. Hypotension with sinus tachycardia and a raised JVP,
which may increase further on inspiration (Kussmaul’s
sign). The pulse is of low volume and reduced on inspi-
Investigations
ration (pulsus paradoxus). Oliguria or anuria develops
Chest X-ray often shows an enlarged globular heart,

which may have very clear borders (because cardiac rapidly and eventually there is hypotension and shock.
movements occur within the fluid and so do not blur
the X-ray). Complications
TheECGshowsreducedvoltageswithvaryingvoltages
If not identified and treated, cardiac tamponade may
between successive beats. rapidly lead to death from low output state.
Echocardiogram is diagnostic with the demonstration

of the echo free zone around the heart, usually poste- Investigations
riorly. Patients are investigated as for pericardial effusion. If
the tamponade is haemodynamically compromising the
Management diagnosis may have to be clinical, but ideally an echocar-
This is determined by the size and haemodynamic ef- diogram is done immediately on suspicion. Echocar-
fect of the effusion. Small effusions (i.e. less than 0.5 cm diogram is diagnostic, can estimate the volume of fluid
separation of pericardium) do not require specific treat- present and assess the severity of cardiac compromise.