Cardiomyopathy is a serious condition in which the heart muscle becomes
inflamed and doesn't work as well as it should. There may be multiple
causes, including viral infections.
Cardiomyopathy can be classified as primary or secondary. Primary cardiomyopathy
can't be attributed to a specific cause, such as high blood pressure,
heart valve disease, artery diseases or congenital heart defects. Secondary
cardiomyopathy is due to specific causes. It's often associated with
diseases involving other organs, as well as the heart.
There are three main types of cardiomyopathy: dilated, hypertrophic and
What is Dilated (Congestive) Cardiomyopathy?
Dilated cardiomyopathy is the most common form. In it, the heart cavity
is enlarged and stretched (cardiac dilation). The heart is weak and doesn't
pump normally, and most patients develop heart failure. Abnormal heart
arrhythmias and disturbances in the heart's electrical conduction also may occur.
Blood flows more slowly through an enlarged heart, so blood clots may form.
- A blood clot that forms in an artery or the heart is called a thrombus.
- A clot that breaks free, circulates in the bloodstream and blocks a small
blood vessel is called an embolus.
- Clots that stick to the inner lining of the heart are called mural thrombi.
- If the clot breaks off the right ventricle (pumping chamber), it can be
carried into the pulmonary blood flow in the lung, causing pulmonary emboli
- Blood clots that form in the heart's left side may be dislodged and
carried into the body's blood flow to cause cerebral emboli in the
brain, renal emboli in the kidney, peripheral emboli or even coronary
How is Dilated (Congestive) Cardiomyopathy Treated?
A person with cardiomyopathy may suffer an embolus before any other symptom
of cardiomyopathy appears. That's why anti-clotting (anticoagulant)
drug therapy may be needed. Arrhythmias may require antiarrhythmic drugs.
Therapy for dilated cardiomyopathy is often aimed at treating the underlying
cause. However, if the person is young and otherwise healthy, and if the
disease gets worse, a heart transplant may be considered.
When cardiomyopathy results in a significantly enlarged heart, the mitral
and tricuspid valves may not be able to close properly, resulting in murmurs.
Blood pressure may increase because of increased sympathetic nerve activity.
These nerves can also cause arteries to narrow. This mimics hypertensive
heart disease (high blood pressure). That's why some people have high
blood pressure readings. Because the blood pressure determines the heart's
workload and oxygen needs, one treatment approach is to use vasodilators
(drugs that "relax" the arteries). They lower blood pressure
and thus the left ventricle's workload.
What is Hypertrophic Cardiomyopathy?
In this condition, the muscle mass of the left ventricle enlarges or "hypertrophies."
In one form of the disease, the wall (septum) between the two ventricles
(pumping chamber) becomes enlarged and obstructs the blood flow from the
left ventricle. The syndrome is known as hypertrophic obstructive cardiomyopathy
(HOCM) or asymmetric septal hypertrophy (ASH). It's also called idiopathic
hypertrophic subaortic stenosis (IHSS).
Besides obstructing blood flow, the thickened wall sometimes distorts
one leaflet of the mitral valve, causing it to leak. Hypertrophic cardiomyopathy
is the most common inherited heart defect, occurring in one of 500 individuals.
Close blood relatives (parents, children or siblings) of such persons
often have enlarged septums. This disease is most common in young adults.
In the other form of the disease, non-obstructive hypertrophic cardiomyopathy,
the enlarged muscle doesn't obstruct blood flow.
The symptoms of hypertrophic cardiomyopathy include shortness of breath
on exertion, dizziness, fainting and angina pectoris. (Angina is chest
pain or discomfort caused by reduced blood supply to the heart muscle.)
Some people have cardiac arrhythmias. These are abnormal heart rhythms
that in some cases can lead to sudden death. Often an implanted cardioverter
defibrillator (ICD) is needed to shock the heart to restart a normal heart
rhythm and prevent sudden death. The obstruction to blood flow from the
left ventricle increases the ventricle's work, and a heart murmur
may be heard.
How is Hypertrophic Cardiomyopathy Treated?
The usual treatment involves taking a drug known as a beta blocker (such
as metoprolol) or a calcium channel blocker. If a person has an arrhythmia,
an antiarrhythmic drug may also be used. Surgical treatment of the obstructive
form is possible in some cases if the drug treatment fails.
Alcohol ablation is a type of nonsurgical treatment for hypertrophic obstructive
cardiomyopathy. It involves injecting alcohol down a small branch of one
of the heart arteries to deaden the extra heart muscle. This allows the
extra heart muscle to thin out without having to cut it out surgically.
What is Restrictive Cardiomyopathy?
This is the least common type in the United States. The myocardium (heart
muscle) of the ventricles becomes excessively "rigid," so it's
harder for the ventricles to fill with blood between heartbeats. A person
with restrictive cardiomyopathy often complains of being tired, may have
swollen hands and feet, and may have difficulty breathing on exertion.
This type of cardiomyopathy is usually seen in the elderly and may be
due to another disease process.