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Hypertrophic Cardiomyopathy Clinic
Hypertrophic Cardiomyopathy (HCM)
Hypertrophic cardiomyopathy (HCM) is an inherited disease that affects certain proteins within heart muscle cells. It is quite common for a genetic disease, affecting approximately one in 500 people.
The normal heart is a four-chamber pump. The walls of the heart are made of layers of muscle cells. The heart rhythm is under the control of the heart’s electrical system. Heart muscle cells respond to an electrical impulse by briskly contracting. When the cells contract together, this squeezes the chamber and blood is pumped forward. Between contractions, the cells relax allowing blood to fill the heart chambers for the next heartbeat. In HCM, the proteins within the muscle cells that allow the cell to contract and relax are abnormal. This results in stiff heart walls that do not relax in the normal way between heartbeats (diastolic dysfunction).
In HCM, the muscle cells are also thick (hypertrophy), causing the heart walls to be thick as well. This effect is seen most in the ventricular septum (the wall between the heart’s two lower chambers-the ventricles). In some cases, the wall becomes so thick that it obstructs the flow of blood out to the body. This can cause symptoms of chest pain during exercise and makes the person more prone to life-threatening abnormal heart rhythms such as ventricular tachycardia or ventricular fibrillation.
While HCM can be a serious problem, many people have only mild disease that causes mild or no symptoms. The course of the disease, severity and health effects vary widely, even among family members. Overall, the risk of serious problems is quite low as long as the hypertrophy (thickening of heart muscle wall) remains mild.
In more severe cases, treatment options include:
- Heart medicines such as calcium channel blockers (verapamil) and beta blockers (propanolol, atenolol) are used to promote heart muscle relaxation
- ICD implantation may be used if life-threatening arrhythmias occur or the patient is at high risk of arrhythmias
- Myomectomy – a heart surgery – is sometimes done if there is a significant blockage of blood flow. In this operation, some of the excess heart muscle is removed.
- Heart transplant may be needed if there are severe symptoms in spite of treatment medical or surgical treatment.
Alcohol septal ablation is a cardiac catheterization treatment for HCM that involves injecting ethanol into the septal artery via a catheter. The septal artery supplies blood to the thickest portion of the heart muscle. The septal artery is blocked and the toxicity of the ethanol kills off the thickened heart muscle cells, causing a controlled heart attack.Overtime, the septum shrinks in size and allows greater blood flow. (Not all HCM patients are candidates for alcohol septal ablation. A cardiologist will evaluate and determine if the patient is a candidate.)
