2 Heart Disease



Hypertrophic Cardiomyopathy

The second most common form of heart muscle disease is hypertrophic cardiomyopathy. Physicians sometimes call it by other names: idiopathic hypertrophic subaortic stenosis (IHSS), asymmetrical septal hypertrophy (ASH), or hypertrophic obstructive cardiomyopathy (HOCM).

In hypertrophic cardiomyopathy, the growth and arrangement of muscle fibers are abnormal, leading to thickened heart walls. The greatest thickening tends to occur in the left ventricle (the heart's main pumping chamber), especially in the septum, the wall that separates the left and right ventricles. The thickening reduces the size of the pumping chamber and obstructs blood flow. It also prevents the heart from properly relaxing between beats and so filling with blood. Eventually, this limits the pumping action.

Hypertrophic cardiomyopathy is a rare disease, occurring in no more than 0.2 percent of the U.S. population. It can affect men and women of all ages. Symptoms can appear in childhood or adulthood.


Most cases of hypertrophic cardiomyopathy are inherited. Because of this, a patient's family members often are checked for signs of the disease, although the signs may be much less evident or even absent in them. In other cases, there is no clear cause.


Many patients have no symptoms. For those who do, the most common are breathlessness and chest discomfort. Other signs are fainting during physical activity, strong rapid heartbeats that feel like a pounding in the chest, and fatigue, especially with physical exertion.

In some cases, the first and only manifestation of hypertrophic cardiomyopathy is sudden death, caused by a chaotic heartbeat. The heart's lower chambers beat so chaotically and fast that no blood is pumped. Instead of beating, the heart quivers.

In advanced stages of the disease, patients may have severe heart failure and its associated symptoms, including fluid accumulation or congestion.


By listening through a stethoscope, a physician may hear the abnormal heart sounds characteristic of hypertrophic cardiomyopathy.  An electrocardiogram (EKG, or ECG) may help diagnose the condition by detecting changes in the electrical activity of the heart as it beats.

Echocardiography is one of the best tools for diagnosing hypertrophic cardiomyopathy.  It uses sound waves to detect the extent of muscle-wall thickening and to assess the status of the heart's functioning.

Physicians also may request radionuclide studies to gather added information about the disease's effect on how the heart is pumping blood.

Other tests that also may provide useful information are the chest x ray, cardiac catherization, and a heart muscle biopsy.


Treatments for hypertrophic cardiomyopathy vary but can include the following:

  • Lifestyle changes. Patients with serious electrical and blood-flow abnormalities must be less physically active.
  • Medications.  Various drugs are used to treat the disease. They include beta blockers (to ease symptoms by slowing the heart's pumping action), calcium channel blockers (to relax the heart and reduce the blood pressure in it), antiarrhythmic medications, and diuretics (to ease heart failure symptoms).

    However, drugs do not work in all cases or may cause adverse side effects, such as fluid in the lungs, very low blood pressure, and sudden death. Then, other treatment, such as a pacemaker or surgery, may be needed.

  • Pacemakers. These change the pattern and decrease the force of the heart's contractions. The pacemaker can reduce the degree of obstruction and so relieve symptoms. A pacemaker needs to be carefully monitored after its insertion in order to properly adjust the electrical impulse. Some patients who have a pacemaker inserted feel no relief and go on to have heart surgery.
  • Surgery. This usually calls for removal of part of the thickened septum (the muscle wall separating the chambers) that is blocking the blood flow. Sometimes, surgery also must replace a heart valve - the mitral valve, which connects the left ventricle and the left atrium, the upper chamber that receives oxygen-rich blood from the lungs.

    Surgery to remove the thickening eases symptoms in about 70 percent of patients but results in death in about 1 to 3 percent of patients. Also, about 5 percent of those who have surgery develop a slow heartbeat, which is then corrected with a pacemaker.

Course of the disease

The course of the disease varies. Many patients remain stable; some improve; some worsen in symptoms and lead severely restricted lives. Patients may need drug treatment and careful medical supervision for the rest of their lives.

Hypertrophic cardiomyopathy patients also are at risk of sudden death. About 2 to 3 percent die each year because the heart suddenly stops beating. This cardiac arrest is brought on by an abnormal heartbeat. Over 10 years, the risk of sudden death can be 20 percent or more.


Click here for additional resources on cardiomyopathy.


Cardiomyopathy - Congestive Cardiomyopathy - Hypertrophic Cardiomyopathy - Restrictive Cardiomyopathy - Additional Resources





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