About Hypertrophic Cardiomyopathy

Cardiomyopathy and Heart Failure

One of the many causes of heart failure is cardiomyopathy. There are two major types of cardiomyopathy: primary cardiomyopathy, defined as changes in the structure or function of the heart muscle that cannot be attributed to a specific cause, and secondary, which is associated with disorders of the heart or other organs. Congestive cardiomyopathy is the most common primary form of heart muscle disease. Other types include hypertrophic and restrictive cardiomyopathy. Heart muscle disease related to coronary artery disease is called ischemic cardiomyopathy.

The causes of primary cardiomyopathy are frequently unknown. Some possible causes in congestive cases are infectious or noninfectious heart muscle inflammation, excessive alcohol consumption, nutritional deficiencies, complications of childbirth, and genetic disorders. Hypertrophic cardiomyopathy appears to be an inherited disease. Restrictive cardiomyopathy is usually caused by a disease called amyloidosis, which is associated with cancers of the blood. Men seem to be affected by congestive cardiomyopathy more often than women. Most cases of cardiomyopathy cannot be prevented. Avoiding smoking and excessive alcohol intake, ensuring proper nutrition, and regular exercise are the only known preventive measures.

The exact frequency of cardiomyopathy is difficult to determine as many cases are not severe, but about 500,000 new cases develop each year in the United States. Instead of afflicting the elderly like most other heart diseases, heart muscle disease more commonly strikes younger people. This group of disorders directly damages the muscle, impairing its ability to pump blood to other parts of the body.

What is Hypertrophic Cardiomyopathy (HCM)?

In congestive cardiomyopathy, also called dilated cardiomyopathy, the heart becomes stretched and weakened and is unable to pump effectively. Symptoms of heart failure develop.

Drawing of two hearts, a normal heart and a heart with a thickened wall between the right and left vertricles, indicating hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM), in contrast to the congestive type, involves thickening of the heart muscle, usually that of the left ventricle, but sometimes the right chamber is also involved. In one form of hypertrophic disease, the septum—the wall between the two ventricles—becomes enlarged and obstructs the flow of blood from the left ventricle into the aorta. The mitral valve also may be distorted by the thickened septum, leading to mitral insufficiency. The major symptoms are shortness of breath, dizziness or fainting, chest pain, and cardiac arrhythmias.

Because the symptoms of HCM mimic those in many other conditions, it is often misdiagnosed as exercise-induced asthma, mitral valve prolapse, or anxiety/depression.

While HCM involves a structural abnormality in the heart muscle, patients often have conduction problems in the biological wiring of the heart as well.

Atrial fibrillation, an irregular rhythm that affects the normal pumping of the heart, is a common complication associated with HCM. Patients may also suffer ventricular tachycardia and other serious arrhythmias.

In addition, blood clots may form in the hypertrophic heart, then travel through the bloodstream, causing a stroke, heart attack, or reduced blood flow to the arms and legs.