Learn about restrictive cardiomyopathy symptoms, diagnosis, and management options. Get informed and find support on Meri Sehat.

Restrictive Cardiomyopathy

PNS SHIFA

Online Consultation

Syed Intisar Hussain

Overview

In restrictive cardiomyopathy (RCM), the cardiac muscles, or more commonly the ventricles, harden, creating hindrance in the chamber&rsquo;s ability to relax and fill with blood. This leads to heart failure and raises pressure on your heart, which in turn causes fluid to build up in your lungs. The symptoms of RCM depend on the disease&rsquo;s severity<a href="#accordion">[5]</a>.

&nbsp;

Restrictive cardiomyopathy (RCM) is essentially a condition in which the chambers of the heart harden over time. Even though the heart is able to pump blood, it doesn&rsquo;t have the luxury to relax between beats as it would do in a disease-free state. This causes early exhaustion and makes it harder for the heart to fill up. Consequently, the blood pools up in your circulatory system, which in turn builds up in the body, including the lungs. Furthermore, this also increases the ventricular pressure and the size of the atria. Your heart rhythm might change, making it impossible to pump as much blood out to the body as it normally would.

RCM is a rare disease. However, it accounts for almost 5% of all cases of cardiomyopathies<a href="#accordion">[1]</a>. There are three major cardiomyopathies, namely: dilated, hypertrophic, and restrictive, where RCM is the least common variant. Amyloidosis is the most common cause of RCM in the United States. Moreover, RCM affects both genders equally. In comparison with other pediatric cardiomyopathies, RCM is less responsive to medical or surgical treatments which then leads to higher mortality rates i.e. 63% within 3 years of diagnosis and 75% within 6 years of diagnosis<a href="#accordion">[8]</a>.&nbsp;

<div>&nbsp;</div>

&nbsp;

<h5>1. Primary/Idiopathic RCM</h5>

Primary RCM is also called classical, non-infiltrative, and idiopathic RCM. It can be defined as a hemodynamic abnormality that occurs without any histological features of myocardial abnormalities. Patients who suffer from idiopathic RCM can present with or without hypertrophied left ventricular (LV) walls, but in almost 57% of the cases, patients present with the familial (hereditary) variant of RCM<a href="#accordion">[4]</a>.

Idiopathic RCM with hypertrophied LV walls is microscopically quite similar to hypertrophic cardiomyopathy. The familial type of idiopathic RCM indicates a genetic abnormality that is usually associated with distal skeletal myopathy (muscular pathology).&nbsp;

A study reported that autosomal dominant RCM presented with atrioventricular block and skeletal myopathy in five generations of an Italian family that symptoms exhibited mostly after 40 years of their lives. Patients with idiopathic RCM also develop a mild to moderate increase in cardiac weight and bi-atrial enlargement, reduced systolic function, and patchy endocardial fibrosis.

&nbsp;

<h5>2. Secondary RCM</h5>

Secondary RCM develops due to an underlying cardiac or systemic disorder that affects the heart. This results in restrictive blood flow which in turn causes RCM. When systemic disorders that aided in RCM were studied, categorization became convenient. Based on these results, it is divided under myocardial and endomyocardial disorders, in reference to the layers of the muscles of the heart.

<div>&nbsp;</div>

Signs And Symptoms

Though RCM usually does not exhibit any symptoms, especially in the earlier stages, this can change with disease progression. Following are a few signs and symptoms that may present:

&nbsp;

<ul>
	<li>Shortness of breath, especially on exertion; if not treated, it may worsen and present as shortness of breath at rest</li>
	<li>Fatigue</li>
	<li>Swelling in the legs and other parts of the body</li>
	<li>Unprecedented unconsciousness</li>
	<li>Weakness or lightheadedness</li>
	<li>Cough</li>
	<li>Abnormal heart rhythm</li>
</ul>

<div>&nbsp;</div>

Causes

Causes of RCM include a variety of factors; certain diseases, health conditions, and environmental factors. Some of these causes are<a href="#accordion">[2]</a>:

&nbsp;

<ul>
	<li>Hemochromatosis: It is a disease in which your body is in iron overload. As an excess amount of iron is toxic to the body, it can present with symptoms of organ damage. One of the most critical organs to be affected is the heart.</li>
</ul>

&nbsp;

<ul>
	<li>Sarcoidosis: Sarcoidosis refers to a disease that essentially causes inflammation and affects the body&#39;s organs. Researchers firmly believe that a pathological immune response may be a reason behind the development of sarcoidosis. This abnormal response forms tiny lumps of cells in the organs, including the heart.</li>
</ul>

&nbsp;

<ul>
	<li>Amyloidosis: There is an abnormal buildup of proteins in the organs, including the heart.</li>
</ul>

&nbsp;

<ul>
	<li>Connective Tissue Disorders</li>
</ul>

&nbsp;

<ul>
	<li>Radiation And Chemotherapy:&nbsp;These treatment options for cancer&nbsp;can also cause RCM.</li>
</ul>

<div>&nbsp;</div>

There is no test which exclusively screens for RCM. However, a routine physical checkup that includes baseline assessments such as CBC, liver function tests and ECG can help look for any progressive changes that may silently exist.&nbsp;

&nbsp;

Diagnosis

Restrictive cardiomyopathy is often mixed with pericarditis when it comes to diagnosis. Pericarditis is essentially an inflammation of the surrounding tissue of the heart. Different diagnostic modalities can help your healthcare practitioner reach an accurate diagnosis. To be sure if you have primary restrictive cardiomyopathy, your doctor will take the presenting symptoms into account, along with your family history of heart disease. Following are the assessments, your doctor might order<a href="#accordion">[3]</a>:

&nbsp;

<ul>
	<li>A Physical Exam: A routine is an important part of your life, and diseases like RCM only emphasize this fact, as RCM is asymptomatic in the beginning. Your doctor goes through your history and vital signs which includes heart rate as well. This helps in establishing a relevant baseline for diagnosing primary restrictive cardiomyopathy.</li>
</ul>

&nbsp;

<ul>
	<li>Electrocardiogram (ECG): ECG is used to record the heart&rsquo;s electrical activity. As it also gives you information on the heart&rsquo;s rhythm and blood flow, an abnormality can be easily detected.</li>
</ul>

&nbsp;

<ul>
	<li>Chest X-Ray: A chest X-ray helps your doctor to visualize any inflammation if present. This is important&nbsp;if inflammation is the cause of restrictive cardiomyopathy. X-ray of the chest can also help to rule out restrictive cardiomyopathy by revealing findings that can be evidence of other diseases e.g., pericarditis.</li>
</ul>

&nbsp;

<ul>
	<li>Echocardiogram: An echocardiogram holds specific importance in diagnosing restrictive cardiomyopathy. The test can report enlargement of the upper chambers of the heart and if any thickening has developed. Furthermore, the test is also able to show the hardening of ventricular walls - a characteristic feature of restrictive cardiomyopathy.</li>
</ul>

&nbsp;

<ul>
	<li>Exercise Stress Test: During this test, you undergo ample physical stress to see how your heart functions.</li>
</ul>

&nbsp;

<ul>
	<li>CT Scan: A heart CT, or Computed Tomography, scan produces highly detailed images of the heart and its blood vessels.</li>
</ul>

&nbsp;

<ul>
	<li>MRI: Magnetic Resonance Imaging is a diagnostic modality that uses a magnetic field and radio waves to produce 2-D and 3-D images of the heart. Because of its accuracy, MRI is highly credible when it comes to differentiating between restrictive cardiomyopathy and pericarditis.</li>
</ul>

&nbsp;

<ul>
	<li>Cardiac Catheterization: A long thin tube is inserted into your artery in the groin and guided&nbsp;up to the heart. With the help of this test, any damage to the heart muscle, valves, and arteries can be accurately seen, and your blood pressure along with the flow can also be measured.</li>
</ul>

&nbsp;

<ul>
	<li>Liver Biopsy: To rule out hemochromatosis, a liver biopsy is done to look for any excess iron. During this procedure, a small needle is inserted into your liver to take a sample.</li>
</ul>

<div>&nbsp;</div>

Treatment

Restrictive cardiomyopathy can be successfully treated but the plan depends upon the severity and the presence of any underlying cause. There are three ways to take control of the disease which include lifestyle changes, medications, and surgery<a href="#accordion">[6]</a>.

&nbsp;

<h5>Lifestyle Changes</h5>

If you are diagnosed with RCM, the first and foremost thing to do is to change your eating habits and physical activity. You should restrict your sodium intake as it can help with restrictive cardiomyopathy symptoms, such as shortness of breath, fatigue, weight gain, and swelling. You should also try to keep a healthy workout routine. However, it must be cleared by your doctor first.

&nbsp;

<h5>Medications</h5>

Medications which are used in the treatment of RCM include:

&nbsp;

<ul>
	<li>Beta Blockers: These drugs work by causing the heart to beat slower and less vigorously, which in turn helps lower the blood pressure. Examples include propranolol.</li>
</ul>

&nbsp;

<ul>
	<li>ACE Inhibitors: ACE&nbsp;inhibitors help to relax the blood vessels and the diastolic blood pressure which improves blood flow. This helps the heart pump blood to the rest of the body relatively easily. Examples include captopril.</li>
</ul>

&nbsp;

<ul>
	<li>Digoxin: Digoxin works by blocking the electrical conduction between your atria and ventricles, creating slower contractions of the lower compartments of the heart. Digoxin does this by controlling the transport of calcium, sodium, and potassium through the heart.</li>
</ul>

&nbsp;

<ul>
	<li>Diuretics: These agents help by reducing swelling. Examples include spironolactone.</li>
</ul>

&nbsp;

<h5>Surgery</h5>

In extremely severe cases, a heart transplant is usually recommended for treating restrictive cardiomyopathies.

<div>&nbsp;</div>

If RCM is allowed to progress, it can cause the following complications<a href="#accordion">[3]</a>:

<ul>
	<li>Heart failure</li>
	<li>Stroke due to a blood clot in the heart which might travel to the brain</li>
	<li>Abnormal heart rhythms</li>
	<li>An exclusive increased risk of complications for pregnant women (volume overload and left or right heart failure)</li>
	<li>Sudden cardiac death</li>
</ul>

<div>&nbsp;</div>

The major risk factors which make you more probable to develop RCM are<a href="#accordion">[2]</a>:

<ul>
	<li>A positive family history of cardiomyopathy, heart failure, or sudden cardiac arrest (SCA)</li>
	<li>A disease, such as <a href="https://www.merisehat.pk/disease/coronary-artery-disease" target="_blank">coronary heart disease</a>, <a href="https://www.merisehat.pk/disease/myocardial-infarction" target="_blank">heart attack</a>, or viral infection, that is capable of inflaming the heart muscle&nbsp;can lead to cardiomyopathy</li>
	<li><a href="https://www.merisehat.pk/disease/diabetes-type-1-and-2" target="_blank">Diabetes </a>or any other metabolic disease</li>
	<li>Diseases that can be proven damaging to the heart, such as hemochromatosis, sarcoidosis, or amyloidosis</li>
	<li>Excessive alcohol intake</li>
	<li>Long-standing high blood pressure</li>
</ul>

<div>&nbsp;</div>

Restrictive cardiomyopathy can take a toll on your heart. Therefore, if there are measures which can reduce your risk of developing RCM, you should try to abide by them. Such factors include<a href="#accordion">[5]</a>:

<ul>
	<li>Constantly monitor and control your blood pressure.</li>
	<li>Maintain a healthy weight.</li>
	<li>Reduce stress.</li>
</ul>

<div>&nbsp;</div>

Researchers have found that angiopoietin-like protein 8 (ANGPTL8) deficiency significantly speeds up cardiac hypertrophy and fibrosis with deteriorating cardiac dysfunction. Hence, giving scientists a new opportunity to look for revolutionary treatments<a href="#accordion">[7]</a>.

&nbsp;

Key Points

<ul>
	<li>In restrictive cardiomyopathy (RCM), the cardiac muscles, or more commonly the ventricles, harden which creates a hindrance in the chamber&rsquo;s ability to fill with blood.</li>
	<li>Your heart rhythm might change, making it impossible to pump as much blood out to the body as it normally would.</li>
	<li>It accounts for almost 5% of all cases of cardiomyopathies.</li>
	<li>There are three major cardiomyopathies, namely: dilated, hypertrophic, and restrictive, where RCM is the least common variant.&nbsp;</li>
	<li>Primary RCM is defined as a hemodynamic abnormality that occurs without any histological features of myocardial abnormalities.</li>
	<li>In 57% of the cases, patients present with the familial (hereditary) variant of RCM.</li>
	<li>Idiopathic RCM, microscopically, is quite similar to hypertrophic cardiomyopathy, when there is an involvement of hypertrophied LV walls.</li>
	<li>A study reported that autosomal dominant RCM presented with atrioventricular block and skeletal myopathy in five generations of an Italian family that symptoms exhibited mostly after 40 years of their lives.</li>
	<li>Secondary RCM develops due to an underlying cardiac or systemic disorder that affects the heart.</li>
	<li>Signs and symptoms may include shortness of breath (especially on exertion), shortness of breath at rest when the disease progresses, fatigue, and swelling in the legs and other parts of the body.</li>
	<li>Causes include hemochromatosis, amyloidosis, sarcoidosis, chemotherapy, and radiation.</li>
	<li>A routine physical checkup that includes baseline assessments such as CBC, liver function tests, and ECG to look for any progressive changes which may be silently existent.</li>
	<li>Diagnostic modalities include ECG, echocardiogram, CT scan, MRI, and&nbsp;physical exam.</li>
	<li>Treatment plan includes lifestyle changes, medications, and a surgical approach.</li>
	<li>Medications include digoxin, ACE inhibitors, and diuretics.</li>
	<li>Complications include heart failure, sudden cardiac death, and abnormal heart rhythm.</li>
	<li>Risk factors include a positive family history of cardiomyopathy, heart failure or sudden cardiac arrest (SCA), diabetes, or any other metabolic disease.</li>
	<li>Preventive factors include constantly monitoring and controlling your blood pressure, maintaining a healthy weight, and reducing stress.</li>
	<li>Researchers have found that angiopoietin-like protein 8 (ANGPTL8) deficiency significantly sped up cardiac hypertrophy and fibrosis with deteriorating cardiac dysfunction.</li>
</ul>

<div>&nbsp;</div>

[1] Brown KN, Pendela VS, Ahmed I, et al. Restrictive Cardiomyopathy. [Updated 2022 Jul 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.

[2] Restrictive cardiomyopathy. American Heart Association.

[3] Restrictive Cardiomyopathy. Cedars Sinai.

[4] Albakri A. Restrictive cardiomyopathy: A review of literature on clinical status and meta-analysis of diagnosis and clinical management. Pediatric Dimensions. 2018;3(2).

[5] Restrictive cardiomyopathy: Causes, symptoms & treatment. Cleveland Clinic.

[6] Restrictive cardiomyopathy symptoms and treatment: Baptist Health.

[7] Hu L, Wei J, Zhang Y, et al. ANGPTL8 is a negative regulator in pathological cardiac hypertrophy. Cell Death & Disease. 2022;13(7). doi:10.1038/s41419-022-05029-8