By Sarah Jividen, RN 

Updated on October 31, 2023

 Medically reviewed by Jeffrey S. Lander, MD

Restrictive cardiomyopathy is a rare heart condition characterized by the stiffening of the heart muscles, which inhibits the heart's ability to relax and fill with blood properly. This reduced flexibility can impair the heart's function and cause symptoms, including arrhythmias or heart failure.¹ Treatment typically focuses on managing symptoms and addressing underlying causes. Getting an early diagnosis is crucial for effective management.²

This article will provide an overview of cardiomyopathy, including types, symptoms, causes, diagnosis, and outlook for the condition.

Natalia Gdovskaia / Getty Images

How Does Restrictive Cardiomyopathy Affect the Body?

Restrictive cardiomyopathy primarily affects the body by causing the ventricles in the heart to become stiff and less compliant. This stiffness restricts the heart's ability to effectively relax and fill with blood, making it harder for your heart to pump blood to the rest of the body.³

Types of Restrictive Cardiomyopathy

Restrictive cardiomyopathy manifests when the heart's ventricles lose their flexibility. This can occur, for example, when abnormal tissue like scar tissue displaces healthy heart muscle.¹

There are several types of restrictive cardiomyopathy. However, the two main classifications are primary and secondary restrictive cardiomyopathy.⁴

Primary or Idiopathic Restrictive Cardiomyopathy

This type occurs without a clear underlying cause, and it's often referred to as "idiopathic." Primary restrictive cardiomyopathy is characterized by the inherent stiffness of the heart's ventricles, primarily the left ventricle, without a specific underlying disease or condition driving the stiffening of the heart muscle.

Primary cases may be genetic and, in many cases, are associated with a worse prognosis than the secondary type.⁴

Secondary Restrictive Cardiomyopathy

Secondary forms are associated with underlying diseases or conditions that lead to the development of restrictive cardiomyopathy. Common underlying causes include:⁴

• Amyloidosis: A condition where abnormal protein deposits (amyloids) accumulate in the heart and other organs, causing them to stiffen.⁵

• Sarcoidosis: An inflammatory disease that can affect various organs, including the heart. It may lead to the formation of granulomas in the heart muscle, causing stiffness.⁶

• Hemochromatosis: A genetic disorder that leads to excessive iron accumulation in the body, including the heart, leading to cardiac stiffness.⁷

• Endomyocardial fibrosis: A condition where fibrous tissue forms within the heart chambers, restricting their ability to fill with blood.⁸

Who Does Restrictive Cardiomyopathy Affect?

Restrictive cardiomyopathy is rare and can affect individuals of various ages, genders, and backgrounds. It is not limited to a specific demographic group. However, it tends to affect older people.¹

 Restrictive Cardiomyopathy

Restrictive Cardiomyopathy Symptoms

Restrictive cardiomyopathy can lead to a range of signs and symptoms, including:⁹

• Shortness of breath (dyspnea), which can occur with exertion or even at rest

• Fatigue

• Edema, or swelling, particularly in the legs, ankles, feet, and neck veins

• Irregular heartbeats or arrhythmias, such as atrial fibrillation

• Exercise intolerance or fainting with exercise

• Chest pain

• Heart murmurs

• Dizziness or lightheadedness

• Cough²

It's important to note that the signs and symptoms of restrictive cardiomyopathy can vary depending on the severity of the condition and the underlying cause. Additionally, some individuals with this condition may not have any noticeable symptoms in the early stages.⁹

What Causes Restrictive Cardiomyopathy?

There are many causes of restrictive cardiomyopathy, which may include:

Infiltrative restrictive cardiomyopathy

This type involves the infiltration of abnormal substances, such as amyloid protein, into the heart muscle. This infiltration results in the stiffening of the heart walls.⁴

Medical conditions that may cause infiltrative restrictive cardiomyopathy include:⁴

• Amyloidosis

• Hunter's syndrome

• Gaucher’s disease

• Hurler’s disease

• Sarcoidosis

Storage disorders

Some rare genetic disorders, such as Fabry disease, can lead to the accumulation of specific substances called myocytes within the heart muscle, causing restrictive cardiomyopathy.⁴

Radiation-induced restrictive cardiomyopathy

Exposure to high-dose radiation therapy, often used to treat cancer, can damage the heart muscle and lead to restrictive cardiomyopathy.¹⁰

Connective tissue disorders

Conditions like scleroderma can affect the connective tissues in the heart, leading to stiffness.⁴ Scleroderma is a chronic autoimmune disease characterized by the hardening and thickening of the skin and, in some cases, involvement of internal organs, such as the heart.¹¹

MedlinePlus. Scleroderma.

Some cancer treatments

Certain chemotherapy drugs can have toxic effects on the heart muscle.¹² This condition is often called "chemotherapy-induced cardiomyopathy." Over time, the heart muscle can become weakened and stiff, leading to restrictive cardiomyopathy.¹³

How Is Restrictive Cardiomyopathy Diagnosed?

Diagnosing restrictive cardiomyopathy typically involves a combination of medical history assessment, physical examination, and various diagnostic tests to evaluate the structure and function of the heart. Your provider will gather your medical history and perform a physical examination. An exam may reveal signs of heart failure or signs of fluid retention.²

Here are the key steps and tests involved in the diagnostic process:²

• Electrocardiogram (ECG or EKG): An ECG records the heart's electrical activity to help identify irregular heart rhythms and other cardiac abnormalities.

• Echocardiography: A test that uses sound waves to create images of the heart.

• Magnetic resonance imaging (MRI): A test that uses magnets and radio waves to provide detailed images of the heart.

• Computed tomography (CT) scan: This scan helps provide additional information about the heart's structure and any abnormalities.

• Blood tests: These help identify any underlying conditions that may be causing or contributing to restrictive cardiomyopathy.

Sometimes, a biopsy of the heart tissue is required to make a diagnosis of restrictive cardiomyopathy.¹⁴

In some cases, other imaging techniques, such as nuclear imaging or positron emission tomography (PET) scans, may be used to assess heart function and detect conditions like cardiac amyloidosis.²

Diagnosing restrictive cardiomyopathy can be complex because the condition often has multiple potential causes, and the presentation of the disease can vary. The diagnostic process aims to determine the underlying cause and assess the extent of heart dysfunction, guiding the development of a treatment plan.

How Is Restrictive Cardiomyopathy Treated?

Restrictive cardiomyopathy is treated by addressing underlying conditions that cause it. There are few well-established treatments for restrictive cardiomyopathy, and the main focus is to manage symptoms to enhance the patient's overall quality of life.²

The following therapeutic approaches are often used to manage symptoms and reduce potential complications:²

• Administration of anticoagulant drugs to prevent blood clot formation

• Chemotherapy (in some cases)

• Diuretics help eliminate excess fluid from the body, improve breathing, and help retain fluids

• Medications regulate or prevent abnormal heart rhythms

Additionally, other treatment modalities may be explored based on the specific subtype of cardiomyopathy, such as:²

• Chemotherapeutic agents

• Medications like tafamidis, designed to target abnormal proteins like amyloid fibrils

• In specific instances, heart transplantation might be considered

Can Surgery Treat Restrictive Cardiomyopathy?

If heart function is severe and causes debilitating symptoms, a heart transplant may be used as a last resort treatment to improve your prognosis and quality of life.²

Does Restrictive Cardiomyopathy Cause Complications?

Restrictive cardiomyopathy can lead to various complications, some of which can be serious and impact a person's overall health and quality of life. These complications typically arise from the impaired ability of the heart to pump blood effectively and fill properly during the cardiac cycle. 

Common complications of restrictive cardiomyopathy include:¹⁵

• Heart failure

• Arrhythmias¹

• Fluid overload

• Hypotension

• Cardiac arrest (rarely)

What’s the Outlook for Someone With Restrictive Cardiomyopathy?

People diagnosed with restrictive cardiomyopathy frequently experience progressive deterioration of heart function, often leading to heart failure. Complications such as irregular heart rhythms or "leaky" heart values may additionally manifest in some cases.²

Heart transplantation may be a potential treatment option for some with restrictive cardiomyopathy. The prognosis is closely tied to the underlying cause of the condition. However, outcomes are often poor. Nevertheless, there are instances where individuals surpass a 10-year survival mark post-diagnosis.²

Summary

In closing, restrictive cardiomyopathy is a rare heart condition characterized by the stiffening of the heart muscles, hindering its ability to effectively pump blood. The primary focus of treatment revolves around managing symptoms and addressing underlying causes. Diagnosing restrictive cardiomyopathy involves a multifaceted approach, including medical history assessment, physical examinations, and a range of diagnostic tests to evaluate heart structure and function.

Complications often arise from the condition's impact on the heart's pumping ability, leading to heart failure, arrhythmias, and fluid overload. Receiving an early diagnosis is essential to optimal management.