Definition

Ventricular aneurysm is a complication of a heart
attack (myocardial infarction). It is a ballooning of a section
of a blood vessel in the heart that first appears several
days or weeks after an acute myocardial infarction.

Description

A myocardial infarction occurs when a section of
the heart wall is deprived of blood and dies (undergoes
necrosis, or tissue death, and scarring). The heart wall is
mainly muscle. It has two ventricles, the right and left
ventricles, which pump blood to and from the lungs, and
to the body. When part of the heart muscle dies, pumping
power from that part of the wall is lost. After a myocardial
infarction, the part of the heart wall that did not die
must continue pumping blood and compensate for the
dead muscle.

Ventricular aneurysm is one of the complications
that follow a myocardial infarction.

An aneurysm is the outward swelling, or ballooning,
of a blood vessel at a weak spot in the wall of the blood
vessel. In the case of ventricular aneurysm, the aneurysm
occurs in the wall of the heart at the spot where the myocardial
infarction occurred. A scar usually forms in the area of
the dead muscle tissue, and may eventually calcify. Ventricular
aneurysms generally do not rupture. The left ventricle
is involved in most cases of ventricular aneurysm.

Causes and symptoms

The principle symptom of a ventricular aneurysm is
cardiac insufficiency, a condition in which not enough
blood is being pumped to the body. Ventricular aneurysm is
usually found after a large infarction in the muscle wall of a
ventricle. Ventricular aneurysm is seldom seen immediately
after a myocardial infarction. It takes several days or
weeks to several months to develop. Frequently, recurrent
ventricular irregular heartbeats (arrhythmias) and low cardiac
output result from the presence of a ventricular
aneurysm. Blood clots (thrombi) may form on the inside
wall of the aneurysm and produce systemic blood clots that
get stuck in a blood vessel (embolisms), which could lead
to stroke or an ischemic leg (a usually painful condition in
which lack of blood circulation leads to reduced function).

Diagnosis

A number of signs may indicate ventricular
aneurysm, including an abnormal precordial impulse in
the heartbeat, persistent elevation of the S-T segment of
an electrocardiogram, and a characteristic bulge seen on
the heart when x-rayed. The bulge is typically seen when
the heart contracts, driving blood to the aorta, in the systolic
phase of the heartbeat. Echolocation (echocardiography
or ultrasound) can confirm the presence of an
aneurysm. Cardiac catheterization may be performed
to determine the extent of the aneurysm and the status of
the coronary arteries. Stethoscopic examination reveals
abnormal heart sounds, especially those associated with
a backflow of blood from the left ventricle to the left atrium
in systole or contraction beat (mitral regurgitation).

This heart murmur is caused by the heart muscles no
longer being able to properly operate the mitral valve.

Treatment

Most cases of ventricular aneurysm are treated by
close medical follow-up and limiting patient activity. Surgical
removal of the aneurysm is an option when persistent
left ventricular failure or arrhythmia occurs, and the
aneurysm is large. Vasodilators, diuretics, and digoxin
are used to treat heart failure. Anticoagulant drugs are
used to prevent the formation of blood clots. Antiarrhythmic
drugs are used to treat heart arrhythmias.

Prognosis

Ventricular aneurysm occurs more frequently than is
commonly thought. Based on postmortem examination,
ventricular aneurysm occurs in as many as 15% of
myocardial infarction cases. Patients with a large ventricular
aneurysm in the left ventricle have a reduced survival
rate. Many patients have mild symptoms which are
not life-threatening. The survival rate is dependent on the
function of the left ventricle.