Treating Hypertrophic Cardiomyopathy

Updated on 2/11/2009

Hypertrophic cardiomyopathy (HCM) is not a curable disease; the primary goals of treatment are to relieve the symptoms and prevent sudden death by:

• promoting heart relaxation
• reducing the obstruction, if present
• avoiding abnormal heart rhythms

Because HCM affects each person differently, there is no "typical patient" and no standard plan of treatment. Furthermore, the treatment rationale for HCM can actually counter the rationale used to treat the same suite of symptoms in a patient who does not have HCM. For instance, many HCM patients have chest pain and shortness of breath—a common symptom of coronary artery disease that is treated with nitroglycerin. If a person with HCM were to take nitroglycerin, the symptoms would worsen and the nitroglycerin could even cause a catastrophic deterioration in the person's condition.

Individualized treatment plans should be developed by cardiologists with an expertise in HCM and be based upon the condition of the heart and the severity of symptoms, as well as the overall health and preferences of the patient. People who have no symptoms and no increased risk for sudden death do not need treatment.

Once symptoms develop, the following treatment options can be considered:

• Medication
• Myectomy
• Septal ablation
• Implantable dual chamber pacemaker
• Implantable cardioverter defibrillator

Medication

In most people with hypertrophic cardiomyopathy, medications successfully relieve the symptoms and let patients maintain a relatively active lifestyle. The drugs that are most effective in treating HCM either slow down the heart rate or reduce the strength of the contractions of the heart muscle. This lets the heart fill more completely with blood between contractions, which minimizes the risk of obstruction and keeps the heart working efficiently. Relaxing the heart muscle, not stimulating it, helps the heart pump more efficiently for people with HCM.

Common Medications Used For Treatment of Patients with Hypertrophic Cardiomyopathy

Beta-blockers are generally the most effective drug and the best tolerated by most patients with HCM, but may require relatively high dosages to be effective. The treatment goal of relieving symptoms may require keeping the resting heart rate at less than 60 beats per minute without compromising the blood pressure levels. However, some people may not tolerate the side effects associated with beta-blockers such as nightmares, impotence, and fatigue.

Calcium channel blockers are a good alternative for individuals who cannot tolerate beta-blockers. Calcium-channel blockers must be prescribed with caution because there have been several reported instances of sudden death after the first dose in patients with very severe obstruction. Dihydropyridine calcium channel blockers should not be prescribed for people with HCM because of the risk of worsening symptoms and sudden loss of consciousness.

Antiarrythmic medication is an alternative for patients who are intolerant of beta-blockers and calcium channel blockers. Although these drugs have been successful in some cases, the side effects of urine retention and dry mouth preclude their use in many patients. The patients who best tolerate antiarrythmics appear to be young women.

Although drug therapy works well for most people, not everyone responds to medications. Others may become intolerant of the drug or develop severe symptoms of HCM after a few years on medications. In these patients, alternative treatments must be considered.

Septal myectomy

Septal myectomy, the surgical removal of a section of heart muscle, is considered by experts to be the most effective and low-risk treatment for symptoms of hypertrophic obstructive cardiomyopathy, in which the heart muscle thickens enough to obstruct the flow of blood. The surgery has been performed for almost 50 years and can dramatically improve symptoms in over 90 percent of patients. The vast majority return to a normal lifestyle with no recurrence of symptoms.

New research indicates that for individuals with HOCM who are symptomatic, myectomy may actually normalize their life expectancy. For patients who have a myectomy, the survival rate at one year is 99 percent; at five years, 98 percent; and at 10 years, 95 percent. This survival rate is the same for the general population. By comparison, for patients with obstruction who do not have a myectomy, survival at one year is 94 percent; at five years, 89 percent; and at 10 years, 73 percent.

As is true for other types of open-heart surgery, myectomy requires general anesthesia and cardiopulmonary bypass, a machine that takes over the functions of the heart and lungs. The procedure lasts three to four hours, including 30 to 45 minutes on cardiopulmonary bypass. The surgeon begins by making an incision in the center of the chest to access the heart. After cardiopulmonary bypass has begun, the surgeon makes an incision in the aorta, entering the heart through the aortic valve to cut away a portion of the overgrown muscle. This physically increases the space inside the left ventricle, removes the obstruction in the heart, and eliminates any regurgitation of blood through the mitral valve. This procedure usually requires five to six days in the hospital with the patient back to work in as soon as six weeks.

The risks from open-heart surgery depend on the patient's general health and age. In a younger, otherwise healthy person, the risk of dying during or shortly after a myectomy performed at a hospital with a lot of experience in the procedure is less then 1 percent; at other hospitals, it can be as high as 5 percent. Fewer than 3 percent of patients experience a complete heart block, in which heart muscle becomes unable to transmit electrical signals, requiring a permanent pacemaker. In fewer than 1 percent of patients, the procedure punctures the septum between the left and right ventricles

The success of a myectomy depends on the technical expertise and experience of the surgical team as well as the type of hypertrophy. Patients have the best outcomes if their surgery is performed at experienced medical centers where the procedure is performed by specialized teams, and the thickening of the heart muscle occurs primarily in the lower part of the septum that separates the left and right ventricles. For individuals with concentric HCM, or thickening of the muscle throughout the heart, myectomy may help alleviate the symptoms of HOCM but may not entirely eliminate them.

Regrowth of the removed muscle after myectomy has not been reported in adults. For children, however, the muscle may grow back, requiring continued medication throughout their lives.

Septal ablation

Septal ablation involves injecting an alcohol solution into the heart, purposely causing a strategically localized "heart attack" to treat the symptoms of hypertrophic obstructive cardiomyopathy by destroying a small area of the muscle. As a new procedure, developed over the past decade, septal ablation is considered experimental by the American Heart Association. Although this procedure is performed using heart catheterization as opposed to open-heart surgery, it is no safer than a myectomy. It's too soon to estimate the long-term benefits and safety issues of septal ablation therapy.

Septal ablation for hypertrophic cardiomyopathy

Septal ablation is a heart catheterization procedure that usually lasts between one and two hours. Patients are awake and able to talk throughout the procedure, although they may be given sedatives to help them relax. Catheters are used to implant a temporary pacemaker, as a safety measure, and to perform an angiography to visualize the blood vessels and small arteries of the heart that carry blood to the overgrown muscle that is causing the obstruction. Once the blood vessels of the overgrown area have been identified, alcohol is injected into the catheter to destroy the tissue in the overgrown area of the heart muscle. Over time, the tissue scars and shrinks, decreasing the obstruction to blood flow and improving the symptoms of HOCM.

While this procedure is relatively new, information from research studies suggests that septal ablation can, in appropriately chosen patients, relieve symptoms to a similar degree as septal myectomy. The success of the treatment largely depends on the ability of the cardiologist to correctly identify and isolate the area of the heart causing the obstruction. Approximately 5 percent to 10 percent of the patients undergoing a septal ablation will need a pacemaker because of damage oto the conduction system of the heart resulting from the procedure. In addition, the procedure is too new for long-term outcomes to be understood. There may be unknown safety issues, such as long-term risks of abnormal and potentially lethal heart rhythms associated with scarring of the heart muscle.

Although many centers are equipped with heart catheterization facilities, it can be very difficult to control the extent of the "heart attack" within the heart muscle. Septal ablation should be performed only by an experienced cardiologist specializing in this procedure.

Not all people with HOCM are candidates for septal ablation. The unique anatomy of each individual heart must be considered; the anatomies of some hearts are not conducive to septal ablation treatment. For some people, there may be other health concerns to consider that preclude the use of this treatment. On the other hand, septal ablation is a good alternative for people who are not candidates for surgery or do not want to undergo heart surgery.

Cardiac pacemaker implantation

Cardiac pacemakers are not the first choice for patients with hypertrophic cardiomyopathy, but they can be used in those who are not candidates for—or don't want to pursue—other treatment options. These small electronic devices, about the size of a stopwatch, monitor the electrical activity of the heart and synchronize the contractions within the heart. When necessary, the pacemaker will send an electrical impulse, which you cannot feel, to stimulate a contraction in a manner that lessens the symptoms of HCM.

Dual chamber pacemakers, which have two leads that attach to the heart, are used to help relieve the symptoms of HOCM. This type of pacemaker allows doctors to modify the sequence of contraction within the heart muscle to help the left ventricle empty before obstruction occurs. The placement of the leads on the heart and the setting of the time delay between the activation of the two leads are crucial to the success of this treatment alternative.

Pacemakers don't work for everyone. Recent trials of patients with HOCM indicate that only 20 percent to 30 percent of patients experience a sustained improvement in their symptoms. Though nearly all patients say they feel better soon after the pacemaker is implanted, many patients report improvements in their symptoms even with the pacemaker turned off, indicating a significant placebo effect.

Pacemakers are implanted in a hospital room equipped with special X-ray equipment. In adults, local anesthesia and sedation are used to minimize any discomfort felt during the procedure. The procedure begins with cleaning the chest with antibacterial soap and starting an intravenous line in the arm. The pacemaker leads are then inserted into a vein under your collarbone and then into your heart; X-rays are used to help guide the placement of the leads. After the leads are in place, the pacemaker is slipped into a small, surgically created pocket under the skin in the upper part of the chest. Over the next 24 hours, the pacemaker will be fine-tuned to your heart rhythm. Upon dismissal, you'll receive a card that identifies you as having a pacemaker.

Ask your doctor about restrictions on activity before you leave the hospital. In most cases, physical activity can gradually be resumed, but the doctor will likely tell you to limit driving and participation in contact sports. The pacemaker must be monitored regularly, which can be done by telephone using a special transmitter. Usually, weekly monitoring is recommended for the first four weeks, then once every three months after that.

General guidelines for people with pacemakers:

• Memorize the name of your device's manufacturer.
• Check with your healthcare provider before starting an exercise program.
• Do not drive until your healthcare provider says you may.
• Stay at least 8 feet away from arc welders.
• Avoid powerful magnets and heavy industrial equipment.
• Do not stand in entryways equipped with retail surveillance/shoplifting devices; walking past at normal speed should not interfere with the pacemaker.
• Keep cellular phones at least 6 inches from the pacemaker and use on opposite side of the implant.
• Do not lean over a running engine; standing next to it is safe.
• Do not have magnetic resonance imaging.
• Before you receive any healthcare, be sure to tell the provider that you have a pacemaker.
• Tell your healthcare provider about your pacemaker before a lithotripsy (procedure used to remove a kidney stone) or any procedures that involve using heat or electricity to burn tissue (cautery, diathermy, or radiation therapy).
• Whenever you have surgery, the surgeon must contact your cardiologist before the surgery because your pacemaker may need to be reprogrammed before the procedure.

Implantable cardioverter-defibrillators

Treatment for the prevention of sudden death is one of the most active areas of investigation in hypertrophic cardiomyopathy. The original treatment to prevent sudden death is the use of antiarrhythmic medications, but recent research indicates that implantable cardioverter-defibrillators may be more effective.

ICDs are highly effective at interrupting potentially lethal heart rhythm disorders. Research in people with HCM has shown that those who have previously experienced a cardiac arrest are quite likely to experience another episode of similar heart rhythms. In these people, the likelihood of the ICD discharging to avert a potentially fatal heart rhythm is 10 percent per year. For other people who have not had cardiac arrest but who are at increased risk for sudden death due to other factors, the likelihood of their ICD interrupting a potentially fatal heart rhythm is about 4 percent to 5 percent per year.

Like cardiac pacemakers, ICDs are small devices that monitor the heart rhythms and send electrical impulses to the heart. If the heart rate becomes dangerously slow, the ICD responds exactly like a pacemaker, sending an electrical impulse that cannot be felt but stimulates the heart to beat. Unlike a pacemaker, ICDs also treat unstable and potentially lethal rhythms such as ventricular tachycardia and ventricular fibrillation. When these rhythms occur, the ICD transmits a succession of low-energy impulses called pacing, or a high-energy shock, or a combination of the two. Usually described as feeling like a kick in the chest, these shocks may be painful, but they last only a fraction of a second, with no lingering pain or damage.

The implantation procedure is done under general anesthesia and requires one to two days of hospitalization. After the anesthetic is administered, the surgeon will make an incision and place one or two electrical leads inside the heart. After the leads are tested, the ICD is implanted in a surgically created pocket near the collarbone. In some instances, an additional lead may be placed under the skin near the rib cage. Usually there is some lingering pain in the area of the incision that can be managed with pain medication. When you are discharged, the hospital will provide a card that identifies you as having an ICD.

After the cardioverter defibrillator is implanted, patients can gradually return to an active lifestyle as recommended by their doctor. There may be some restrictions on driving a car or other vehicle, and a stress test may be necessary to ensure your safety and prevent any unintended shocks. Doctors can adjust the electrical programming of ICDs without additional surgery. In addition, you will need to keep a written diary of any electrical therapy given by the ICD—including when it happened, what you were doing, any symptoms experienced before the shock, and how your body responded.

General precautions for ICDs include:

• Avoid contact sports.
• Avoid medical procedures such as magnetic resonance imaging, lithotripsy (a procedure to remove kidney stones), and cautery (using heat or electricity to burn tissue).
• Tell the healthcare provider you have an ICD before receiving radiation therapy or diathermy (therapy that uses electricity to generate heat).
• Do not allow airport security personnel to use hand-held metal detectors on your body. Ask to be searched by hand.
• Avoid magnetic fields and keep strong magnets away from the ICD.
• Stay at least 8 feet away from arc welders.
• Show medical personnel the ICD card when receiving care.

Emotional support and encouragement from family members and friends are very important part of helping patients live with their heart condition and ICDs. Other ways family members can participate in the medical care:

• Complete a cardiopulmonary resuscitation lifesaving course.
• Help maintain a diary and an ID bracelet or necklace with up-to-date medical information.
• Memorize the name of the ICD manufacturer.
• Be prepared to show medical personnel the ICD card when healthcare is being administered.