Restrictive Cardiomyopathy

Overview

Restrictive cardiomyopathy is one of the main types of cardiomyopathy, or heart muscle disease. In this condition, the walls of the heart, particularly the lower pumping chambers (the ventricles), become stiff and rigid. As a result, the heart cannot relax and fill with blood normally between beats, even though its squeezing function may be relatively preserved, at least early on. Because the chambers fill poorly, less blood is pumped to the body, and pressure backs up into the lungs and the rest of the circulation.

Restrictive cardiomyopathy is the least common of the major cardiomyopathy types. It can result from conditions that infiltrate or scar the heart muscle, and sometimes the cause is unknown. Over time, the impaired filling can lead to heart failure, with symptoms such as fatigue, breathlessness, and swelling. Treatment focuses on managing symptoms, treating any underlying cause, and addressing complications. Early diagnosis and specialist care are important.

Symptoms

Symptoms develop because the heart cannot fill and pump efficiently, leading to congestion and reduced blood flow:

• Fatigue and reduced ability to exercise
• Shortness of breath, at first with activity and later even at rest
• Swelling in the legs, ankles, feet, or abdomen
• Difficulty breathing when lying flat or waking at night short of breath
• Palpitations or an irregular heartbeat
• Lightheadedness or fainting
• Loss of appetite or a bloated feeling from fluid buildup in the abdomen

Severe or sudden breathlessness, chest pain, fainting, or a very rapid or irregular heartbeat are warning signs that need urgent medical attention, as they can indicate worsening heart failure or a dangerous rhythm.

Causes

Restrictive cardiomyopathy occurs when the heart muscle becomes stiff, scarred, or infiltrated by abnormal substances. Causes include:

• Infiltrative diseases: Conditions in which abnormal proteins or cells build up in the heart muscle, such as amyloidosis or sarcoidosis.
• Storage diseases: Inherited disorders that cause substances like iron to accumulate in the heart.
• Scarring (fibrosis): Including scarring after radiation therapy to the chest or certain other conditions.
• Endomyocardial disease: Conditions that thicken and scar the inner lining of the heart.
• Idiopathic: In some cases, no specific cause is identified.

Risk Factors

• Conditions that deposit abnormal substances in the heart, such as amyloidosis
• Inflammatory conditions like sarcoidosis affecting the heart
• Inherited storage disorders, such as those causing iron overload
• Previous radiation therapy to the chest
• A family history of certain cardiomyopathies
• Older age, for some causes such as certain types of amyloidosis

Diagnosis

Diagnosing restrictive cardiomyopathy involves confirming the abnormal heart filling and searching for the underlying cause:

• Echocardiogram: An ultrasound of the heart that shows how the chambers fill and pump and often suggests a restrictive pattern.
• Electrocardiogram (ECG): Records the heart's electrical activity and can show abnormalities.
• Cardiac MRI: Provides detailed images of the heart muscle and can identify scarring or infiltration.
• Blood tests: To look for underlying causes such as iron overload or markers of certain diseases.
• Heart catheterization and biopsy: Measuring pressures inside the heart and, in some cases, taking a small tissue sample to identify the cause.

Treatment

Treatment aims to relieve symptoms, treat the underlying cause when possible, and prevent complications:

• Treating the underlying disease: Specific therapies for causes such as amyloidosis, sarcoidosis, or iron overload, which can change the course of the condition.
• Managing fluid buildup: Diuretic medications to reduce swelling and breathlessness, used carefully to avoid lowering filling too much.
• Controlling heart rhythm: Medications or devices to manage irregular heartbeats, and blood thinners when there is a risk of clots.
• Managing heart failure: Other heart failure treatments tailored to the individual.
• Advanced therapies: In severe cases, a pacemaker or defibrillator, and occasionally heart transplantation, may be considered.
• Lifestyle measures: Limiting salt, monitoring fluid and weight, staying as active as advised, and avoiding alcohol and tobacco.

Because restrictive cardiomyopathy is uncommon and has many possible causes, care is usually guided by a heart specialist (cardiologist), often at a center experienced with heart muscle disease.

Prevention

Many causes cannot be prevented, but some steps may help reduce risk or limit progression:

• Manage and treat conditions known to affect the heart muscle, such as iron overload or sarcoidosis
• Attend recommended follow-up if you have had chest radiation
• Limit salt, monitor weight, and follow your treatment plan to reduce fluid buildup
• Avoid alcohol and tobacco, which can stress the heart
• Report a family history of cardiomyopathy so relatives can be evaluated when appropriate

When to See a Doctor

See a doctor if you have unexplained fatigue, shortness of breath with activity, swelling in the legs or abdomen, or palpitations, especially if these are new or worsening. These symptoms warrant evaluation of the heart, and early diagnosis allows treatment to begin sooner.

Seek emergency care immediately for severe or sudden shortness of breath, chest pain, fainting, or a very rapid or irregular heartbeat, and call emergency services if someone collapses or stops breathing. These can signal a serious heart problem that needs urgent treatment.

Related Topics

Frequently Asked Questions

References

1. American Heart Association. Cardiomyopathy.
2. Mayo Clinic. Restrictive cardiomyopathy — Symptoms and causes.
3. National Heart, Lung, and Blood Institute (NHLBI). Cardiomyopathy.
4. MedlinePlus, U.S. National Library of Medicine. Cardiomyopathy.