Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C)
What is Arrhythmogenic Right Ventricular Dysplasia / Cardiomyopathy?
Arrhythmogenic right ventricular dysplasia / cardiomyopathy (ARVD/C) is a rare familial disorder that may cause ventricular tachycardia and sudden cardiac death in young, apparently healthy individuals. The clinical hallmark of the disease is ventricular arrhythmias, arising predominantly from the right ventricle. The pathological hallmark of the disease is fibrofatty replacement of right ventricular myocardium.
What causes ARVD/C?
ARVD/C is caused by mutations in genes that encode desmosomal proteins. These proteins are involved with cell-to-cell adhesion. This important observation helps explain why ARVD/C is more common in athletes, and the delayed onset of the disease.
What are the symptoms of ARVD/C?
Symptoms of ARVD/C include:
- Arrhythmias– An abnormality in the timing or pattern of a heartbeat that presents as a racing heartbeat, skipping heartbeat, palpitations or fluttering sensation
- Premature Ventricular Contractions– extra or irregular heartbeats that occur when the electrical signal starts in the lower chamber of the heart (the ventricle)
- Ventricular Tachycardia (VT)– a series of rapid heartbeats, originating in the ventricle. This may last only a few beats or may continue and lead to life-threatening arrhythmias. VT can cause weakness, nausea, vomiting and lightheadedness, as well as feelings of a racing or skipping heart.
- Syncope– Also referred to as fainting or a sudden loss of consciousness
- Heart failure– Rarely a patient’s first symptoms are those associated with right heart failure including weakness, foot and ankle swelling (peripheral edema), fluid build-up in the abdomen (ascites), as well as arrhythmic symptoms.
- Sudden cardiac arrest– In some patients, the first sign of ARVD/C is sudden cardiac arrest, where the heart stops beating and pumping blood to the rest of the body’s organs. This can result in death if not treated within minutes.
How is ARVD/C diagnosed?
The diagnosis of ARVD/C is based on meeting a set of specific criteria that take into account ECG abnormalities, arrhythmias, structural abnormalities and tissue characteristics, as well as family history and genetics. In 1994, an international task force proposed criteria for the clinical diagnosis of ARVD/C, based on these various categories. These criteria were very specific to ARVD/C, however they lacked sensitivity in diagnosing milder or atypical presentations. These diagnostic criteria were revised in 2010 and now incorporate advances in both technology and genetics. Information from electrocardiograms (ECGs), signal-averaged ECGs, exercise stress tests, Holter monitors, echocardiograms, MRIs, family history and genetic testing is important when applying the diagnostic criteria. View a comparison chart of the ARVD/C diagnosis criteria for 1994 and 2010.
The Diagnostic Criteria for ARVD/C
A definite diagnosis of ARVD/C consists of the following criteria options from different categories:
- Two major criteria, or
- One major and two minor criteria, or
- Four minor criteria
A borderline diagnosis consists of the following criteria options from different categories:
- One major and one minor criteria, or
- Three minor criteria
A possible diagnosis consists of the following criteria options from different categories:
- One major criteria, or
- Two minor criteria
There is no single test that can either establish or exclude ARVD/C. The criteria that is used to determine ARVD/C is a physical exam, family history, various cardiac tests and genetic information. Tests may include:
- Signal-Averaged Electrocardiogram
- 24-hour Holter Monitor
- Exercise Stress Test
- Cardiac Magnetic Resonance Imaging (MRI)
- Cardiac Computed Tomography (CT)
- Genetic Testing
- Electrophysiology Study
- Right Ventriculogram (RV angiogram)
- Cardiac Biopsy
How is ARVD/C treated?
Treatment options vary by patient, and are based on a patient’s cardiac test results, medical history and the presence or absence of genetic mutations. The three most common treatments for arrhythmias are medication, implantable cardioverter defibrillators (ICDs) and catheter ablation.
Medications can be used to decrease the number of episodes and the severity of an arrhythmia. Medications alter the electrical properties of the heart in one of two ways:
- Directly: The medications affect the electrical currents in the heart
- Indirectly: Medications such as beta blockers block the effects of adrenaline or improve blood flow to the heart.
Beta blockers lower the heart rate, blood pressure and the effects of adrenaline. They are a safe and commonly used type of medication.
If patients experience ventricular tachycardia despite treatment with beta blockers, antiarrhythmic medications, such as sotolol or amiodarone may be recommended. ACE-inhibitors may also be helpful in reducing the workload on the heart and preventing the development of heart failure. Please keep in mind that all medications can cause side effects and that new medications are being developed every year.
Implantable cardioverter defibrillators are commonly used to treat patients with ARVD/C. These devices continuously monitor the heartbeat and automatically deliver a small electrical shock to the heart if an irregular heart beat or rapid sustained heart rhythm occurs. This may cause a momentary discomfort, which is described by some patients as being “kicked in the chest.”
ICDs also can function as pacemakers and can treat both slow and fast rhythms. They should be checked every three to six months and may need to be replaced every four to six years.
To treat ARVD/C with catheter ablation, the areas of the heart causing arrhythmias are located and cauterized (burned) to destroy the tissue. This invasive procedure is performed in an electrophysiology laboratory and can reduce the frequency of arrhythmic episodes.
Traditional catheter ablation, called endocardial ablation, treats the muscle in the inside surface of the heart. Catheters are sent through veins in the legs and followed up into the heart where an arrhythmic area is located and destroyed. Recently, a promising ablation technique called epicardial ablation has been developed. In this technique, the outside of the heart is treated. Many ARVD/C arrhythmias come from the outside of the heart. In epicardial ablation the catheter goes under the breast bone and into the sac around the heart. While an epicardial ablation can be very effective at treating arrhythmias in ARVD/C patients, this is a complicated procedure. We recommend having the procedure performed at a center with experience in treating patients with ARVD/C using this epicardial approach.
Catheter ablation is not a final cure for ARVD/C, because it is a progressive condition. Catheter ablation can help reduce the need for ICD therapy. It is important for patients to have a careful discussion with their physicians about the risks and benefits of catheter ablation before undergoing this procedure.
What is the prognosis for ARVD/C?
Some patients will have a stable functioning heart for decades, while others may have spells of arrhythmias that require changes in medication or ablations. Research has shown that the long-term outlook for most people with ARVD/C is relatively good. Few patients develop such severe dysfunction or frequent episodes of ventricular tachycardia that a heart transplant may be necessary.
The major condition that needs to be differentiated from ARVD/C is idiopathic ventricular tachycardia arising from the outflow tract. Ventricular tachycardia can be exactly the same, but there is no structural abnormality of the heart, unlike the situation in ARVD/C where commonly there is dilation of the ventricle, abnormal contraction or reduced function. Right ventricular outflow tract tachycardia is more common than ARVD/C and occurs in young, otherwise healthy people. The treatment is either with medications or with catheter ablation.