Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic condition in which normal cardiac muscle becomes replaced with fibrous, fatty tissue, mainly in the right ventricle, one of the four chambers of the heart. ARVC is one of the cardiac conditions associated with sudden death, especially in young athletes.

ARVC is uncommon, but not rare. It would be found in 1 out of every 2,000 to 5,000 adults if they were evaluated for it. The underlying genetic mutations that can cause ARVC may be even more common.

This article explains the genetic cause and symptoms of ARVC. It discusses how healthcare providers diagnose and treat arrhythmogenic right ventricular cardiomyopathy.

What Are the Symptoms of ARVC?

While ARVC is a cardiomyopathy—that is, a heart muscle disease—it only rarely causes muscle problems that are extensive enough to produce heart failure.

Rather, its clinical significance is that it can cause abnormal heartbeats (cardiac arrhythmias). In particular, ARVC can cause premature ventricular complexes, ventricular tachycardia, and sometimes ventricular fibrillation.

The symptoms caused by ARVC are usually related to the arrhythmias it may produce. People with ARVC will commonly describe episodes of one or more of the following:

• Palpitations
• Lightheadedness
• Syncope

Sudden death may also occur. Unfortunately, it may be the very first sign that there is any heart problem. In up to 10% of cases, the diagnosis only occurs after sudden cardiac death or resuscitation.

While ARVC can cause sudden death at any time, this event appears to be more likely to occur during episodes of physical exertion than at rest. This is why ARVC is one of the conditions that produces sudden death in apparently healthy, young athletes.

However, because this can also occur during routine activity or at rest, refraining from exercise is generally not enough to alleviate the risk in people with ARVC.

How Is ARVC Diagnosed?

Doctors can diagnose ARVC by examining the results of heart-related tests including:

• Electrocardiogram (ECG or EKG), which often shows a particular configuration of the QRS complex (a waveform showing electrical activity in the heart before the ventricles contract)
• Echocardiogram (echo), which often shows characteristic abnormalities in the cardiac muscle of the right ventricle (and sometimes of the left ventricle)

Cardiac magnetic resonance imaging (MRI) and cardiac computed tompgraphy (CT) may help, as can other tests and techniques such as:

• Holter monitor recordings
• Cardiac stress test
• Cardiac biopsy (tissue sample)

While electrophysiologic testing can occasionally be helpful in distinguishing ventricular tachycardia due to ARVC from ventricular tachycardia caused by other cardiac conditions, such testing is not routinely helpful and is usually not required.

ARVC Treatment

The main goal in treating ARVC is to prevent sudden cardiac death from ventricular tachycardia or fibrillation. This may be done with:

• Activity restrictions
• Medication
• An implantable defibrillator
• Ablation procedures

Activity Restrictions

The arrhythmias associated with ARVC appear to be brought out by sympathetic stimulation—the part of the autonomic nervous system that increases adrenaline levels and is responsible for the fight-or-flight response. This is why exercise is a problem with ARVC.

Because sudden death is often associated with exercise in this condition, athletes who have ARVC should refrain from all competitive sports, with the possible exception of low-intensity activities such as golf or bowling.

Furthermore, they should refrain from any activity that produces significant palpitations or syncope.

Asymptomatic people are also warned that intense exercise increases the risk of developing ARVC symptoms including sudden death.

Medication

Most cardiologists treating this condition recommend the use of beta blockers to blunt the effect of adrenaline in the heart. Yet for people diagnosed with ARVC who have no high-risk features on evaluation and no symptoms, treatment may or may not include beta blockers.

The American Heart Association and American College of Cardiology suggest a beta blocker may be useful. However, the Heart Rhythm Society doesn't believe there is enough evidence to support long-term beta-blocker treatment for unaffected carriers of the gene responsible for ARVC.

Some people may also be prescribed an antiarrhythmic drug, though evidence of benefit remains limited despite their wide use.

Defibrillators

Implantable defibrillators are frequently recommended for people with ARVC, especially when any of the following apply:

• A person has experienced an episode of cardiac arrest
• A person has experienced an episode of sustained ventricular tachycardia
• A person has experienced an episode of unexplained syncope
• Imaging shows extensive involvement of the cardiac muscle

In people with ARVC who have had sustained ventricular arrhythmias, the long-term prognosis appears to be improved if they avoid exercise, take beta blockers, receive an implantable defibrillator, and (in some cases) take an antiarrhythmic drug. Prognosis also depends on which parts of the heart are involved and other individual factors.

Cardiac Ablation

A cardiac ablation may offer benefits, especially when other treatments for ARVC haven't worked well. It is a procedure used to reset heart arrhythmias, and relies on a small catheter inserted into the heart tissue. Radiofrequency ablation relies on radio waves to heat the target tissue.

Summary

Arrhythmogenic right ventricular cardiomyopathy is a genetic condition that can produce potentially lethal cardiac arrhythmias, including those that cause sudden death in young athletes.

In some cases, ARVC goes undetected until sudden death occurs, so it's important to get tested if you have a history of this condition in your family. With aggressive treatment, including medication and implantable devices, people with ARVC typically do quite well.