Arrhythmogenic Cardiomyopathy (ARVC)

What happens in arrhythmogenic cardiomyopathy

Heart muscle cells are held together by protein junctions called desmosomes. In most people with ARVC, a gene variant weakens these junctions. Under mechanical stress, especially intense exercise, cells detach and die and are replaced by fat and fibrous scar. Electrical signals travel unevenly around the scar, setting up ventricular tachycardia, a dangerous fast rhythm from the lower chambers. Over time the affected ventricle may stretch and weaken, leading to heart failure.

The disease usually starts in the right ventricle (ARVC), but the left ventricle is often involved too, and some forms are left-dominant. The broader term "arrhythmogenic cardiomyopathy" covers all of these.

Symptoms

Symptoms usually start between the teens and 40s:

• palpitations: a racing, pounding or irregular heartbeat, often during or after exercise
• lightheadedness or fainting, especially with exertion
• breathlessness or reduced exercise capacity
• chest discomfort
• in later stages, swelling of the legs, belly and neck veins from right-sided heart failure

Some people have no warning symptoms, and sudden cardiac arrest can be the first sign, particularly in young athletes. ARVC is one of the leading causes of sudden cardiac death in young people and athletes.

Causes and genetics

• Inherited gene variants: most often in desmosome genes such as PKP2 (plakophilin-2, the most common), DSP, DSG2, DSC2 and JUP. Other genes include PLN, TMEM43, FLNC and DES.
• Inheritance: usually autosomal dominant: each child of an affected parent has a 50% chance of inheriting the variant. Not everyone with the variant develops disease, and severity varies, even within families.
• Rare recessive forms (Naxos disease and Carvajal syndrome) also cause woolly hair and thick skin on palms and soles.
• Exercise: endurance and high-intensity exercise speeds disease development and raises arrhythmia risk in people who carry the gene.

Diagnosis

There is no single test. Cardiologists use internationally agreed criteria (the Task Force criteria and their updates) that combine:

1. 12-lead ECG: inverted T waves in the right chest leads, an epsilon wave, or other changes.
2. Holter or event monitor: counts extra beats from the ventricles and detects runs of ventricular tachycardia.
3. Echocardiogram: right ventricular enlargement, poor movement or bulging areas.
4. Cardiac MRI: the best imaging test, showing ventricle size and function and sometimes scar.
5. Exercise test: may provoke arrhythmias.
6. Genetic testing: identifies a disease-causing variant in about half of people diagnosed, allowing testing of relatives.
7. Electrophysiology study or heart biopsy: occasionally used.

Conditions that can look similar include athlete's heart, myocarditis, sarcoidosis of the heart, Brugada syndrome and other cardiomyopathies.

Treatment

Exercise restriction

People with ARVC, and gene carriers, are advised to avoid competitive sports and endurance or high-intensity training. Low to moderate recreational activity, such as walking, golf or light cycling, is usually allowed after discussion with a cardiologist. Exercise restriction is one of the most effective measures to slow progression.

Medicines

• Beta-blockers: reduce the effect of adrenaline on the heart and lower arrhythmia risk.
• Antiarrhythmic drugs: such as sotalol, amiodarone or flecainide combined with a beta-blocker, for frequent arrhythmias.
• Heart failure medicines and diuretics if the ventricles weaken.

Implantable cardioverter-defibrillator (ICD)

An ICD is placed under the skin and monitors the heart rhythm. If a dangerous rhythm occurs, it delivers pacing or a shock to restore a normal rhythm. It is recommended for people who have survived cardiac arrest or sustained ventricular tachycardia, and for others judged high-risk using validated risk calculators that consider fainting, arrhythmia burden, ECG changes and ventricle function.

Catheter ablation

Burning or freezing the scarred areas that produce ventricular tachycardia, often from both the inside and outside surface of the heart, reduces episodes and ICD shocks.

Advanced options

Heart transplant is considered for severe heart failure or uncontrollable arrhythmias.

Family screening

Because ARVC is inherited, first-degree relatives (parents, siblings, children) should be offered:

• genetic testing for the family's variant, if one is found
• ECG, Holter monitoring and cardiac imaging, starting around age 10 to 12 and repeated every 1 to 3 years through adulthood

Genetic counseling helps families understand testing, results and implications for insurance and family planning.

Outlook

With modern management, most people with ARVC live into older adulthood. ICDs have greatly reduced sudden death. Progression is variable. Some remain stable for decades while others develop heart failure. Regular follow-up in a specialist inherited heart disease clinic is recommended.

Frequently asked questions

What is arrhythmogenic cardiomyopathy?

It is an inherited heart muscle disease in which muscle cells, usually in the right ventricle, are replaced by fat and scar tissue. The scarring causes dangerous ventricular arrhythmias, palpitations and fainting, and in later stages can weaken the heart's pumping.

Can you exercise with ARVC?

People with ARVC should avoid competitive sports and endurance or high-intensity exercise, which can speed the disease and trigger arrhythmias. Low to moderate recreational activity is usually allowed. Your cardiologist will give individual advice based on your risk.

Is ARVC hereditary?

Yes, in most cases. It is usually inherited in an autosomal dominant pattern, so each child of an affected parent has a 50% chance of carrying the gene variant. Relatives should be offered genetic testing and heart screening.

What is the life expectancy with ARVC?

With diagnosis, exercise restriction, medicines and an ICD when needed, many people with ARVC have a near-normal life expectancy. The main risks, sudden cardiac death and heart failure, are greatly reduced by modern treatment and regular follow-up.

What is the difference between ARVC and ARVD?

They are the same condition. ARVD (arrhythmogenic right ventricular dysplasia) is the older name. ARVC (cardiomyopathy) is now preferred, and "arrhythmogenic cardiomyopathy" is the broader term that includes forms affecting the left ventricle.