Arrhythmogenic Cardiomyopathy
An inherited disease that scars the heart muscle and triggers dangerous rhythms
Quick Facts
- Type: Inherited (genetic) heart muscle disease
- Main risk: Abnormal heart rhythms, sudden cardiac arrest
- Often affects: Younger adults and athletes
- Seek urgent care: Fainting, racing heartbeat, collapse
Overview
Arrhythmogenic cardiomyopathy is a disease of the heart muscle in which normal, working muscle is slowly replaced by fatty and fibrous (scar) tissue. This change weakens the affected chambers and, more importantly, creates electrical "short circuits" that can trigger fast and dangerous heart rhythms. The condition most often affects the right ventricle, which is why it was long called arrhythmogenic right ventricular cardiomyopathy (ARVC), but it can also involve the left ventricle or both.
The disease is usually inherited and caused by faulty genes that affect the tiny connections holding heart muscle cells together. Because the abnormal tissue builds up gradually, many people feel well for years before symptoms appear. The greatest concern is that an abnormal rhythm can occur suddenly, sometimes during intense exercise, which is one reason the condition is an important cause of sudden cardiac arrest in young people and athletes. With diagnosis, treatment, and activity adjustments, the risk of serious events can be substantially reduced.
Symptoms
Symptoms vary widely. Some people have no warning signs and are diagnosed only after screening because a relative was affected. When symptoms do occur, they often relate to abnormal heart rhythms or, later, to a weakening heart.
- Palpitations, a fluttering, pounding, or racing heartbeat
- Lightheadedness or dizziness, especially during or just after exercise
- Fainting (syncope), which can be a serious warning sign
- Shortness of breath or reduced exercise tolerance
- Swelling in the legs, ankles, or abdomen as the heart weakens over time
- Chest discomfort in some people
In some cases the very first sign is sudden cardiac arrest, when the heart stops beating effectively. Anyone who collapses, stops breathing, or has no pulse needs emergency services and CPR immediately, and an automated external defibrillator (AED) should be used if one is available.
Causes
Arrhythmogenic cardiomyopathy is most often caused by inherited changes (mutations) in genes that build the desmosomes, the structures that glue heart muscle cells to one another and help carry electrical signals. When these connections are weak, muscle cells detach and die under the stress of each heartbeat and are replaced by fat and scar tissue.
- Genetic inheritance: Most cases run in families, often passed down so that a child of an affected parent has a meaningful chance of inheriting the gene.
- Intense exercise: Endurance and high-intensity sport places repeated mechanical strain on the heart and can speed up disease progression in people who carry the gene.
Not everyone who inherits a faulty gene develops the disease, and the severity varies even within the same family. A small number of cases have no clear genetic cause identified.
Risk Factors
- A parent, sibling, or child with arrhythmogenic cardiomyopathy or unexplained sudden death at a young age
- Carrying a known disease-causing gene change
- Participation in competitive endurance or high-intensity sports
- Being a young to middle-aged adult, when the disease most often becomes apparent
- A personal history of unexplained fainting or palpitations
Diagnosis
No single test confirms the diagnosis. Doctors combine results from several assessments and review family history.
- Electrocardiogram (ECG): Records the heart's electrical activity and may show characteristic patterns.
- Echocardiogram and cardiac MRI: Imaging tests that show the size, motion, and structure of the heart chambers and can reveal scar or fatty tissue.
- Holter monitor or event recorder: Wearable monitors that capture abnormal rhythms over hours or days.
- Exercise stress testing: Assesses how the heart behaves with exertion.
- Genetic testing: Can identify a disease-causing gene and guide screening of relatives.
Treatment
Treatment focuses on preventing dangerous rhythms, protecting against sudden cardiac arrest, and supporting heart function. The plan is tailored to each person's risk.
- Activity modification: Reducing or stopping intense and competitive exercise is one of the most important steps and can slow progression.
- Medications: Beta blockers and antiarrhythmic drugs help control abnormal rhythms; heart failure medicines may be added if the heart weakens.
- Implantable cardioverter-defibrillator (ICD): A small device placed under the skin that monitors the rhythm and delivers a shock to restore a normal beat if a life-threatening rhythm occurs. It is recommended for people at high risk.
- Catheter ablation: A procedure to target and disable areas of heart tissue causing abnormal rhythms in selected cases.
- Advanced heart failure care: Rarely, a heart transplant may be considered if the heart fails despite treatment.
Lifelong follow-up with a heart specialist, ideally one experienced in inherited heart disease, is essential.
Prevention
The disease itself cannot be prevented because it is usually genetic, but serious events can often be prevented through awareness and care.
- Family screening, including ECG, imaging, and sometimes genetic testing, for close relatives of an affected person
- Avoiding competitive and high-intensity endurance sports if you carry the gene or have the disease
- Taking prescribed medicines consistently
- Promptly reporting fainting, palpitations, or new symptoms to your doctor
- Ensuring family and teammates know basic CPR and how to use an AED
When to See a Doctor
See a doctor if you have unexplained palpitations, fainting, or a strong family history of arrhythmogenic cardiomyopathy or sudden death at a young age, especially if you are an athlete. Seek emergency care right away for:
- Fainting or near-fainting, particularly during exercise
- A sustained racing or pounding heartbeat that does not settle
- Chest pain, severe breathlessness, or collapse
If someone collapses and is unresponsive with no normal breathing, call emergency services, start CPR, and use an AED if available.
Frequently Asked Questions
Is arrhythmogenic cardiomyopathy inherited?
Yes, most cases are caused by inherited gene changes and can run in families. Because of this, close relatives of an affected person are usually offered heart screening and sometimes genetic testing, even if they feel well.
Can people with this condition still exercise?
Light to moderate everyday activity is often fine, but intense and competitive endurance sport can speed up the disease and trigger dangerous rhythms. Exercise should always be discussed with a cardiologist who can give individual advice.
Why is an ICD sometimes recommended?
An implantable cardioverter-defibrillator continuously watches the heart rhythm and can deliver a shock to restore a normal beat if a life-threatening rhythm occurs. It is offered to people at higher risk of sudden cardiac arrest as a safeguard.
What are the warning signs I should not ignore?
Fainting (especially during exercise), a sustained racing heartbeat, and severe breathlessness are important warning signs and need prompt medical assessment. Collapse with no pulse or breathing is an emergency requiring CPR and emergency services.
Can the condition be cured?
There is currently no cure, but treatment can greatly reduce the risk of dangerous rhythms and manage symptoms. Many people live full lives with medication, activity adjustment, and, when needed, a defibrillator and regular specialist follow-up.
References
- American Heart Association. Arrhythmogenic Right Ventricular Cardiomyopathy.
- National Heart, Lung, and Blood Institute (NHLBI). Cardiomyopathy.
- Mayo Clinic. Cardiomyopathy — Symptoms and causes.
- MedlinePlus, U.S. National Library of Medicine. Arrhythmogenic right ventricular dysplasia.