Download What is ARVC? Arrhythmogenic Right Ventricular Cardiomyopathy

What is ARVC?
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is a disease of the heart muscle. It is a
genetic condition and therefore it can be passed on through families. In 40% of patients with clinical
ARVC a genetic defect may not yet be identified. Paramount for the diagnosis is the examination of
the electrocardiogram (ECG) and echocardiogram. The disease is progressive over the time and it can
have different manifestations also among people of the same family sharing the same genetic defect
(mutation). Not everyone who inherits the mutation (carrier) will develop the clinical condition and
there is no way of predicting who will develop the full disease or how severe it will be.
How does ARVC affect the heart?
The genetic defect results in a change in the heart muscle. In people with a normal heart, the muscle is
held together by proteins: in people with ARVC these proteins are abnormal and not well developed.
This causes a fragmentation of the heart muscle: some part of the muscle dies, becomes scarred and
can be replaced by fat. As a consequence, the walls of the heart become thin and stretched, the heart
does not contract properly and the normal passage of the electrical impulses is impaired. This may
cause life-threatening abnormal heart rhythms and in some cases sudden cardiac death. Initially, it was
described as disease of the right side of the part (right ventricle) but the changes in the heart muscle
can also affect the left side.
What are the symptoms of the ARVC?
Some people with ARVC present no symptoms, others do. ARVC patients may develop get shortness
of breath (dyspnea) and/or swelling of the ankles or legs (edema). These occur usually when the heart
is severely affected and the pumping action of the heart is significantly reduced. Patients may also
experience palpitations (sensation of an extra or skipped heartbeat) and/or fainting (syncope, loss of
consciousness). These may be caused by an erratic heart rhythm (arrhythmia): in the parts of the heart
muscle affected, the electrical impulse may become disrupted as it crosses the areas of damaged and
scarred heart. This can lead to slow, fast or erratic heart rhythm. When the arrhythmia is fast and
originates from the lower side of the heart (ventricle), it can cause syncope as the rhythm is so fast and
unstable that does not allow the heart to pump adequately. If the ventricular arrhythmia does not stop,
then a cardiac arrest or sudden death can occur.
When should the diagnosis be suspected?
Your doctor may suspect that you have ARVC because of your symptoms or because of the result of
an ECG or echocardiogram. You may be going for investigations because someone else in your family
has been diagnosed with the disease or has history of unexplained syncope. You may also be screened
because in your family there is history of sudden death in young people.
How is the diagnosis made?
As changes of the heart may be very subtle and can be caused by other conditions, the diagnosis of
ARVC can be difficult. The most common tests for ARVC are:
- Abnormal resting ECG
- Signal-averaged ECG
- 12-lead 24-hour Holter recording (this is a continuous ECG)
- Echocardiogram
- Cardiac Magnetic Resonance
- Genetic testing
Diagnosis is made according to international guidelines: a score is assigned to any abnormality found
in the tests. According to the score, a patient can be diagnosed with ARVC or being considered as
possibly affected. The molecular screening involves all major disease-causing genes for ARVC.
How is ARVC inherited?
ARVC is usually inherited by autosomal dominant transmission. This means that each child of a
person affected by ARVC has a 50% chance of inheriting the genetic defect. To carry the genetic
mutation does not imply that the disease will become clinically manifest. This is known as incomplete
penetrance.
Who in an ARVC family should undergo genetic screening?
Genetic test allows finding the disease-causing mutation in almost 40-60% of the patients. Family
members of a patient with ARVC can be affected, and it is therefore important that, if the responsible
mutation has been identified all other first-degree relatives are also screened. This will rapidly allow
knowing who in the family is or is not affected, and this will lead to the institution of preventive
strategies for protection. ARVC is a progressive disease, and a mutation carrier still without symptoms
may develop them in the future. As intense exercise facilitates the progression of the disease,
asymptomatic mutation carriers are advised to avoid competitive sport or intense exercise.
What is the treatment and who should be treated?
At present there is no cure for ARVC but there are treatments available that aim at reducing the risk of
developing symptoms or to help relieve them and to prevent complications. The main objectives of the
clinical management are: to identify subjects at high risk for sudden cardiac death and offer protective
measures; to prevent or control arrhythmias; to improve the pumping action of the heart muscle, if
necessary. For high risk individuals an ICD may be considered. At present, the ICD is used for
patients with a definitive diagnosis and symptoms (cardiac arrest, syncope or palpitations). Patients
with the genetic diagnosis but no symptoms and manifestations should be followed on a regular basis.