What are the other Names for this Condition? (Also known as/Synonyms)

• Idiopathic Myocardial Fibrosis Induced Restrictive Cardiomyopathy
• Infiltrative Restrictive Cardiomyopathy
• RCM (Restrictive Cardiomyopathy)

What is Restrictive Cardiomyopathy? (Definition/Background Information)

• Restrictive Cardiomyopathy (RCM) is the most infrequent of the known cardiomyopathies. The condition can occur in individuals of any age. Cardiomyopathy is a term used for a variety of conditions that affect the muscles of the heart
• Restrictive Cardiomyopathy is characterized by heart muscle dysfunction that does not allow them to relax, and consequently, results in decreased filling of the lower chambers (ventricles) of the heart with blood, between heartbeats. Occasionally, the contraction of the heart muscles that allows the pumping of blood, may also be restricted in RCM
• In some cases, Restrictive Cardiomyopathy is inherited, and having a family history of the condition is a risk factor for developing it. Medical conditions, such as endocardial fibroelastosis (the congenital form in children), amyloidosis, scleroderma, heart tumors, and scarring of heart tissue owing to various heart conditions, are some known risk factors for developing RCM
• Mutation(s) in the TNNI3 gene are known to cause the inherited form of Restrictive Cardiomyopathy. This gene codes for troponin I protein, which, when mutated, does not allow the heart muscles to relax completely. The mutation is inherited in an autosomal dominant pattern, in which a single defective copy of the gene in each cell of the individual is sufficient to cause RCM
• The signs and symptoms of Restrictive Cardiomyopathy include shortness of breath during exertion or while resting, fainting, fatigue, chest pain, and irregular heartbeats. Children with the congenital form of RCM may not grow or gain weight normally
• The diagnosis of Restrictive Cardiomyopathy involves a thorough physical examination, symptom assessment, echocardiography (ECG), electrocardiography (EKG), stress test, coronary catheterization, chest X-ray and other imaging tests. If required, a biopsy of the heart muscle may be ordered
• Some potential complications of Restrictive Cardiomyopathy include aberrant heartbeats (arrhythmia), sudden cardiac arrest, development of blood clot, stroke, and fluid build-up in the tissues and organs
• The treatment options for Restrictive Cardiomyopathy are symptomatic, and aimed at improving an affected individual’s quality of life. These may include the use of steroidal treatments, blood-thinning medications, diuretics, and anti-arrhythmia drugs
• If RCM occurs because of other medical conditions, then getting treated for those medical conditions may help delay its progression. Additionally, the affected individuals may improve their quality of life by leading an active life, losing excess weight, stopping smoking, discontinuing drug and alcohol use, and eating a balanced and nutritious meals
• Restrictive Cardiomyopathy worsens over time, and therefore, the prognosis of the condition is generally poor. On an average, the survival rate following diagnosis is 7 years. A few individuals may live beyond 10 years following diagnosis of RCM

Who gets Restrictive Cardiomyopathy? (Age and Sex Distribution)

• Restrictive Cardiomyopathy is a very rare heart condition, accounting for approximately 5% of all cardiomyopathies
• The onset of RCM can vary; it can occur at any age. In children with the condition, the age of onset is typically 5-6 years, and young girls appear more prone to it than boys
• The disorder can affect all populations (racial and ethnic groups)

What are the Risk Factors for Restrictive Cardiomyopathy? (Predisposing Factors)

The following are some known risk factors for developing Restrictive Cardiomyopathy:

• A family history of the condition
• Endocardial fibroelastosis
• Sarcoidosis
• Amyloidosis
• Hemochromatosis
• Scleroderma
• Heart tumors
• Certain treatment for cancers
• Obesity
• Smoking, drug abuse, and alcoholism

Note: Several medical conditions can lead to RCM. Whatever the underlying cause, the result is the formation of scar tissue in the heart muscles, which compromises their flexibility. This does not allow them to relax completely, in order for blood to fill the lower heart chambers.

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Restrictive Cardiomyopathy? (Etiology)

Restrictive Cardiomyopathy may be primary, caused by inherited gene mutation(s), or secondary (which develops consequential to a pre-existing condition). Some causes for the condition include:

Genetic factors: Mutation(s) in TNNI3 gene, among several other uncharacterized gene mutations.

• Under normal circumstances, the gene codes for cardiac troponin I protein, which forms the “troponin protein complex” with two other proteins. This complex aids in the contraction and relaxation of the heart muscles in a rhythmic manner
• The mutations in the TNNI3 gene results in the formation of a defective protein that compromises the formation and functioning of the troponin protein complex. This in turn affects the contraction and relaxation of the heart muscles
• The mutation is inherited in an autosomal dominant manner. In this type of inheritance, a single defective copy of the mutated gene is sufficient to cause the disease. The affected individuals inherit the defective gene from an affected parent

Certain health conditions:

• Amyloidosis: It is a systemic disease that results in the build-up of amyloid proteins in tissues and organs, including the heart. This condition is more common in adults
• Endocardial fibroelastosis: It is a disease characterized by an increased thickening in the muscles that layer the heart chambers. This leads to an increase in fibrous tissue in the heart, with a subsequent enlargement of the organ. Endocardial fibroelastosis typically affects infants
• Hemochromatosis, a genetic condition that causes excess iron in the body. This can lead to iron toxicity in many organs, including the heart via iron accumulation
• Sarcoidosis: It is a systemic disease that can affect several parts of the body, leading to the growth of small lumps of inflammatory cells. The disease affects the heart by causing abnormal rhythms and electrical conductivity problems
• Hypereosinophilic syndrome (HES): It is a rare type of blood disorder. In this disorder, there is abnormally elevated number of eosinophils, which are a type of white blood cells involved in immune functions. These cells penetrate tissues and organs, including the heart muscles
• Scleroderma, an autoimmune disorder in which an individual’s immune cells destroy his/her own healthy cells
• Tumors in the heart, including those from carcinoid syndrome, which is a rare slow-growing type of tumor predominantly affecting organs of the GI tract

Cancer therapy:

• Chemotherapeutic treatment for cancer, which can generate scar tissue
• Radiation therapy for cancer that can cause scarring of tissues

What are the Signs and Symptoms of Restrictive Cardiomyopathy?

The symptoms of Restrictive Cardiomyopathy may include:

• Chest pain, coughing
• Dizziness, fainting
• Shortness of breath with physical activity/exertion
• Shortness of breath while lying down (Orthopnea)
• Palpitations; a sensation of rapid, fluttering or pounding heartbeat
• Swelling of ankles, legs, abdomen or veins in the neck
• Fatigue
• Low urine output; urge to urinate frequently at night (particularly in adults)
• Lack of concentration
• Reduced appetite

How is Restrictive Cardiomyopathy Diagnosed?

Restrictive Cardiomyopathy is diagnosed with information from the following tests and exams:

• A thorough physical examination and assessment of symptoms
• Evaluation of personal and family medical history
• Blood test to check for heart disease markers, levels of iron, and various blood cell types such as eosinophils
• Chest X-ray to check for heart size, contour, or fluid build-up in lungs
• Other imaging tests of the heart using techniques, such as computed topography (CT) scan and magnetic resonance imaging (MRI) scan
• Electrocardiogram (EKG) to check the heart’s electrical activity
• Echocardiography (ECG or echo) uses sound waves to create a moving picture of the heart. This helps to check the size, shape, and pumping function of the heart 
• Nuclear imaging of the heart with “multigated acquisition” scan (MUGA scan), to determine the heart’s pumping function (specifically, the functioning of the ventricles)
• Cardiac catheterization: To check for pressure and blood flow in the heart’s chambers. It is often coupled with coronary angiography, in which a harmless dye is injected into the coronary arties and with the help of an X-ray, blood flow through heart and blood vessels can be observed
• Myocardial biopsy: A piece of the heart is removed and the cells are investigated for changes that may suggest damage to heart muscle. The biopsy can also provide information regarding ongoing myocardial infections, if any

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Restrictive Cardiomyopathy?

The following are some potential complications associated with Restrictive Cardiomyopathy:

• Arrhythmias: Abnormal heart rhythm, which can be triggered by physical exertion
• Sudden cardiac arrest (which can be unexpected)
• Embolism: Development of blood clots in the heart which may get into the bloodstream and obstruct blood supply to many important organs
• Edema: Fluid buildup in the lungs, abdomen, legs, and feet; all consequences of ineffective heart pumping
• Stroke

How is Restrictive Cardiomyopathy Treated?

The treatment options for Restrictive Cardiomyopathy are aimed at improving the quality of life of those affected, by providing symptomatic and supportive care. The following are some treatment modalities:

• Treatment for primary medical conditions that led to RCM, which may include:
  • Use of steroids for sarcoidosis
  • Removing blood from the body to reduce iron overload in hemochromatosis
  • Chemotherapy for shrinking tumors
• Lifestyle changes:
  • Adhering to a healthy diet that includes fresh fruits, vegetables, whole grains, fish and dairy products
  • Engaging in routine physical activity
  • Smoking cessation
  • Losing excess weight
  • Avoiding alcohol and illicit drugs
  • Getting enough sleep
  • Avoiding or reducing of stress
• Prescription medications such as:
  • Beta blockers and calcium channel blockers, generally the first choice of medicines to treat cardiomyopathies, to regulate heartbeats
  • Digoxin, to improve heart function and increase activity level
  • Diuretics, to remove excess fluid and sodium
  • Electrolytes to aid in the proper functioning of muscles and nerve tissues
  • Anti-coagulants or blood thinners, which prevent blood clot formation
  • Anti-inflammatory drugs, to reduce inflammation 
• Non-surgical procedures such as alcohol septal ablation
• Surgical procedures, through the use of surgically-implanted devices:
  • Implantable cardioverter defibrillator (ICD): It is a small device implanted in the chest or abdomen and connected to the heart via wires. The device helps control life-threatening arrhythmias that can lead to sudden cardiac arrest. The procedure is typically recommended for younger individuals
  • Pacemakers, generally recommended for older adults
  • Left ventricular assist devices (LVADs) or heart pumps

How can Restrictive Cardiomyopathy be Prevented?

Restrictive Cardiomyopathy cannot be prevented, if it occurs as a result of inherited gene mutations.

• Genetic testing and counseling of prospective parents with a family history of the condition may help in understanding RCM better
• If RCM occurs secondary to any medical condition, then treatment of the primary factor may help decrease or delay the occurrence of the condition
• Regular medical screening at periodic intervals with tests and physical examinations are strongly recommended
• Some lifestyle changes, such as following a healthy diet, quitting cigarettes, reducing alcohol drinking, getting regular exercise and reducing stress, may help prevent the severity and complications from the condition
• In high-risk individuals, implantable cardioverter defibrillator, pacemaker, or a heart pump may help prevent sudden cardiac arrest, a potential complication of Restrictive Cardiomyopathy

What is the Prognosis of Restrictive Cardiomyopathy? (Outcomes/Resolutions)

• The prognosis of Restrictive Cardiomyopathy is dependent upon the severity of the signs and symptoms and the cause of RCM
• The prognosis is generally poor; the average survival after diagnosis is approximately 7 years
• Medications and supportive care may help the affected individuals lead a better quality of life

Additional and Relevant Useful Information for Restrictive Cardiomyopathy:

Please visit our Heart & Vascular Health Center for more physician-approved health information:

http://www.dovemed.com/healthy-living/heart-center/