ABOUT THE DISEASE

Unfortunately, there is no current cure or treatment that can return the heart to normal or guarantee long term survival. Although occasionally children with certain types of cardiomyopathy do improve, the vast majority do not show any recovery in heart function. If detected in the earlier stages, cardiomyopathy may be controlled with long-term drug therapy and placement of a pacemaker/ defibrillator.

If the disease is diagnosed at an advanced stage, critically ill patients may require immediate lifesaving measures such as placement of a breathing tube (mechanical ventilator) and administration of medications intravenously (i.e. dobutamine, dopamine) to improve blood pressure and heart function. Once the patient has stabilized, therapy involving oral medication, implantable devices, surgery or heart transplantation will be considered.

A child's medical management should be done in consultation with a pediatric cardiologist, and possibly a cardiothoracic surgeon, electrophysiologist, and geneticist. It is important to do a comprehensive evaluation to pinpoint the cause so that proper preventative measures can be taken. Since each type of cardiomyopathy has distinct symptoms with a varying course, patients will require an individualized treatment plan for the acute and chronic management of the disease. Several factors will determine the required therapy such as the child's age, overall health, medical history, stage of the disease, and the child's tolerance for specific medications, procedures or therapies. The physician will also try to determine the extent of risk for 1) sudden death 2) predisposition to progressive symptoms 3) atrial fibrillations and 4) predisposition to end stage heart failure. Because children grow at such rapid rates, frequent visits to the cardiologist are essential for monitoring changes in the heart and preventing complications.

Every physician will try to restore a child's health to the best possible state with a minimum of interventional procedures. In general, the aim of medical therapy for a child with dilated cardiomyopathy is to 1) control symptoms of congestive heart failure, 2) improve heart function and contracting ability and 3) prevent complications such as blood clots or arrhythmias. Treatment specifics for a child with hypertrophic cardiomyopathy are somewhat similar in that the goal is to 1) control symptoms related to heart obstruction, 2) improve filling of heart chambers and 3) prevent arrhythmias and risk of sudden death.

Drug Therapy

Various medications will be given as the first line of treatment for the disease if symptoms are present. The choice and dosage of drugs will depend on each individual's diagnosis and may be modified over time as the child grows or responds to the medication. Basically drug therapy is used to relieve heart failure symptoms, decrease the workload on the heart, decrease the oxygen requirements of the heart and regulate abnormal heartbeats. Although drug therapy is noninvasive, there are some side effects and it requires careful monitoring to prevent other complications. It is important to note that many drug therapies are based on treatment of adult cardiomyopathy. There is still some debate about whether there is increased risk of toxicity and reduced effectiveness in children because they metabolize drugs differently than adults.

Dilated Cardiomyopathy

Patients with dilated cardiomyopathy may be given angiotensin converting enzyme (ACE) inhibitor or anti congestive medications such as captopril, enalapril and spironolactone. These medications relax the arteries in the body and decrease the amount of work the heart needs to pump blood to the body. Lasix and aldactone are common diuretics used to reduce excess fluid in the lungs or other organs. Digoxin is used to improve the pumping function of the heart and to prevent certain types of arrhythmia. Based on the long-term benefits found on adults, other medications such as beta-blockers and aldosterone may also be used in children. Some children with severe heart dysfunction may also require anticoagulation medications such as Warfarin to prevent blood clotting or anti-arrhythmic medications such as amiodarone for ventricular arrhythmias.

Hypertrophic Cardiomyopathy

For patients with hypertrophic cardiomyopathy, the most serious problems are decreased heart filling, arrhythmia and obstruction to blood flow by the thickened heart muscle. Diuretics and digoxin are not usually used with HCM patients with obstruction because these drugs can worsen the obstruction of blood flow out of the heart. Instead, beta blockers and calcium channel blockers are prescribed to patients with moderate to severe obstruction. Medications such as propranolol and verapamil may be given to decrease the outflow obstruction by slowing the heart rate and relaxing the heart. Antiarrhythmic medications such as amiodarone and disopyramide may also be required to reduce the risk of sudden cardiac death.

Restrictive Cardiomyopathy

Patients with restrictive cardiomyopathy are at a high risk for blood clots within the heart, particularly in the enlarged upper chambers. Anticoagulation medication or blood thinners such as heparin and coumadin may be prescribed along with a mild dose of diuretics to relieve venous congestion. Beta-blockers and diuretics are also often prescribed.

Arrhythmogenic Right Ventricular Cardiomyopathy

In the rare case that a child is diagnosed with arrhythmogenic right ventricular cardiomyopathy, medications to control arrhythmias and end stage congestive heart failure will be recommended.

Left Ventricular Non-Compaction Cardiomyopathy

For the child with left ventricular non-compaction cardiomyopathy (LVCM) that has symptoms of heart failure, medical treatment with diuretics, ACE inhibitors, and possibly beta-blockers may be used to alleviate symptoms and potentially help the heart muscle structure to normalize. If the patient shows signs of significant arrhythmia, antiarrhythmic medications such as amiodarone or sotalol, have been used for prevention of sudden death. In patients felt to be at risk for clot formation, anticoagulants such as aspirin are used. Patients with associated metabolic disorders may be given a mitochondrial metabolic disorder cocktail of Q10, thiamine, ribloflavin, and carnitine. Once LVCM is diagnosed, a neurological evaluation should be considered because of the high risk of associated neuromuscular disorders.

Device Implantation

A pacemaker or defibrillator is used when drugs are not effective in alleviating obstruction or when dangerous arrhythmias need to be regulated. The procedure involves implanting a small mechanical device under the skin of the chest or abdomen with wire leads threaded through veins into the heart. It is considered minor surgery, requiring a short hospital stay. Once a pacemaker or defibrillator is inserted, it requires careful monitoring to determine when it needs to be replaced and to ensure that the electrical settings are correct. The decision to implant a pacemaker or defibrillator depends on the specific heart problem.

Pacemaker (PPM)

A pacemaker is used to monitor and stabilize slow heartbeats. Dual chamber pacing has been used in older children and adults with obstructive hypertrophic cardiomyopathy to decrease outflow obstruction. Although this procedure is not recommended for infants or small children, recent advances have allowed for single chamber pacing in younger children.

Automatic Implantable Cardioverter
Defibrillator (AICD)

An automatic internal cardioverter defibrillator (AICD) is used to detect and treat very fast, lethal heart rhythms. Often referred to as an "emergency room in the chest", an AICD will send a small electrical shock to the heart to reduce it to normal levels if a dangerously high heart rate occurs. It may benefit higher risk patients who have experienced serious episodes of fainting, been resuscitated from cardiac arrest, have experienced life threatening arrhythmias or are susceptible to sudden death.

Sudden death accounts for 50% of deaths in children with hypertrophic cardiomyopathy, and it has been reported that children with restrictive cardiomyopathy have a 28% incident rate of sudden death. Therefore, defibrillators are often recommended for children diagnosed with HCM, RCM and ARVD who show evidence of arrhythmias. There are also devices available that combine the function of a pacemaker and defibrillator and provide protection from both abnormally slow and rapid heart rhythms.

Surgical Options

Myectomy

A septal myectomy is recommended in a few cases for symptomatic children with obstruction associated with hypertrophic cardiomyopathy. This surgery is done primarily to reduce heart failure symptoms related to restricted blood flow from the ventricles or severe leakage (known as mitral regurgitation). This procedure requires the surgical removal of part of the thickened septal muscle that is blocking the blood flow. In some cases, the mitral valve that connects the heart's lower chambers (left ventricles) with the upper chamber (left atrium) is replaced with an artificial valve.

Myectomy is considered major heart surgery with an attendant recovery time both in the hospital and at home. Although the surgery is quite effective in reducing severe symptoms in HOCM patients, it does not prevent sudden death related to arrhythmias. It also does not "control" or stop the disease from progressing. As with any type of openheart surgery, there is always the risk of complications or death but this only affects 1-3% of patients. In addition, a small number of patients that have a myectomy develop a slow heartbeat, which then requires placement of a pacemaker. Given these issues, it is unclear whether the procedure is of great benefit to children with HOCM.

There are no proven surgical techniques for dilated cardiomyopathy in children. Techniques performed on adults such as cardiomyoplasty (encasing the heart within another muscle and using a pacemaker like device to improve pumping function) and ventricular remodeling (a tiny portion of the diseased heart is removed) are not recommended for children.

Heart Transplantation

Since cardiomyopathy can become a progressive condition, the heart can deteriorate to the point where it does not respond to medication or surgery. A heart transplant is the last resort when the patient reaches the "end stage" of the disease and experiences severe disability and heart failure symptoms.

Cardiomyopathy is the leading reason for heart transplantation in children. Roughly 20% of infants and children with symptomatic cardiomyopathy require a transplant within the first year of diagnosis. While a donor heart can cure all the symptoms of heart failure and greatly improve survival, it is considered a major operation with considerable risks. Once a transplant is done, there are other possible issues to deal with such as infection, organ rejection, coronary artery diseases and side effects to the heart medications that treat these risks.

For a physician, the most difficult decision is determining when a patient should be listed for a transplant. Since donor hearts for infants or young children are scarce, there may be a long wait for a donor heart that matches the required weight and blood type of the child. Cardiologists generally do not want to list too early when there is still a possibility that the heart function may improve or stabilize. It is also not advisable to wait until there is severe heart failure and the child's overall health deteriorates. The child may then be too weak to survive a transplant operation or a suitable donor heart may not become available in time.

Extremely sick patients may require placement on an artificial heart-lung machine called ECMO to sustain them until they are able to receive a suitable organ. However, ECMO is only a short-term bridge to transplant option with neurological consequences to consider. For older children over 50 kilograms, a circulatory support device called the "Heart Mate Left Ventricular Assist System" by Thoratec may be used to "buy time" for end stage heart failure patients while they wait for a donor heart. It has been successful in extending a patients life by 3 to 12 months while providing a better quality of life during the waiting process.

Additional Treatments

Genetic Testing

Family screening is often missed because the focus is on attending to the child with cardiomyopathy. However, identifying who may be affected is important for family planning as well as assessing the risk to relatives and siblings.

Since cardiomyopathy can be inherited and present without any signs or symptoms, it is recommended that all first-degree relatives of a patient (parents, siblings, children) be screened. It is also advisable to screen grandparents, aunts, uncles, and cousins. This is especially the case if there is a family history of sudden infant death or sudden cardiac arrest. Even if there is no evidence of the disease, it is advisable to screen more than once. For children with an affected family member (parent or sibling) but without symptoms, an echocardiogram and ekg should be regularly scheduled every 1 to 3 years prior to age 12 and then more frequently from age 12 to 21. If by early adulthood there is no evidence of cardiomyopathy, it is unlikely that the condition will develop. However, those with a family history of cardiomyopathy may be advised to continue screening every 5 years throughout life even after the age of 21. These are general screening guidelines that may need to be adjusted on an individual basis by the evaluating cardiologist. Factors that typically influence the frequency of screening include: 1) type of cardiomyopathy diagnosed, 2) family history indicating the likelihood of familial cardiomyopathy and 3) clinical presentation profile of the affected family member.

Alternatively, if a specific genetic diagnosis can be determined (i.e. cardiomyopathy related to another syndrome), other siblings should be genetically tested to see if they are at risk for the disorder and cardiomyopathy. This type of testing can lead to a better defined prognosis and more targeted therapy.

Specialized Metabolic Treatment

When a metabolic cause of cardiomyopathy is suspected or confirmed, a child may require specific treatment measures in addition to the above cardiac procedures. In order to maintain the child's biochemical stability, this may involve careful dietary monitoring of certain fats, avoidance of fasting, prompt intervention during common childhood illness, and possibly a daily prescription of carnitine. Infants and younger children who require frequent feedings may also need to have a gastrointestinal feeding tube inserted to prevent episodes of hypoglycemia during illness or dehydration.