Left ventricular pseudoaneurysm with pericardial leak
is defined as a rupture of the myocardium that is contained by pericardial
adhesions or the epicardial wall. Myocardial rupture directly causing
death reportedly occurs in 7% to 10% of patients after acute myocardial
infarction; pseudoaneurysm, a contained rupture, is reportedly a rare
complication of myocardial infarction. Pseudoaneurysm can also occur after
cardiac surgery, chest trauma, and endocarditis. The wall of a pseudoaneurysm
consists of fibrous tissue and lacks the structural elements found in
a normal cardiac wall.
Various imaging methods have been used to diagnose pseudoaneurysm, including
two-dimensional echocardiography, computed tomography, magnetic resonance
imaging, and left ventricular angiography. Chest radiography sometimes
shows a localized bulge on the cardiac silhouette.
Contrast angiography was the first imaging method used to detect pseudoaneurysms.
The presence of a periventricular sac that communicated with the left
ventricle through a narrow orifice was considered most suggestive of a
pseudoaneurysm. This finding differs from findings in a true aneurysm,
which typically has a large communicating neck. In addition, pseudoaneurysms
appear avascular on coronary angiography.
The echocardiographic detection of pseudoaneurysm was first reported in
1975. The echocardiographic features typical of pseudoaneurysms include
sharp discontinuity of the endocardial image at the site of communication
of the pseudoaneurysm with the left ventricular cavity and an orifice
that is relatively narrow in comparison with the diameter of the pseudoaneurysm.
Pulsed-wave and color flow Doppler echocardiography have been useful in
visualizing the high-velocity, turbulent, bi-directional flow between
the left ventricle and a pseudoaneurysm.
On computed tomography, pseudoaneurysms are characterized by an abrupt
disappearance of the myocardial wall at the border of the pseudoaneurysm.
Magnetic resonance imaging shows the low signal of the pericardium, which
constitutes the only wall of the pseudoaneurysm.
An important clinical feature of pseudoaneurysms is their reported propensity
for further rupture and fatal outcome. Because of these observations,
early surgery is recommended even for asymptomatic patients.