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:
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.
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.