Revision 18 for 'Arrhythmogenic right ventricular cardiomyopathy'All Revisions
Arrhythmogenic right ventricular dysplasia
Arrhythmogenic right ventricular dysplasia (ARVD) is classified as type of cardiomyopathy. It is seen particularly in young males, and is one of the more common cause of sudden death in these patients.
The estimated population prevalence is thought to range around 1 in 1000-5000 8. It typically presents in young individuals. There is a recognized male predilection, with a male-to-female ratio of 2.7:1. Several reports suggest that there is a familial occurrence of ARVD of about 30-50%, with mainly autosomal dominant inheritance, various penetrance, and polymorphic phenotypic expression.
ARVD is characterized clinically by ventricular arrhythmias with left bundle branch block (LBBB) that may lead to cardiac arrest. As such it may present as a sudden onset collapse or syncopal episode and should be a consideration in a young fit individual with such a presentation.
- as the name implies this is associated with fatal arrhythmias and sudden cardiac death.
- other non fatal arrhythmias include
- left bundle branch block : LBBB
- ventricular tachycardia
Diagnosis is based on the presence of structural, histologic, electrocardiographic, arrhythmic, and genetic factors 4. This involves a combination of characteristic abnormalities in family history, electrocardiography, cardiac imaging as well as endomyocardial biopsy.
Diagnostic criteria have also been developed, of which patients must have either two major criteria, one major and two minor criteria, or four minor criteria. See diagnostic criteria for arrthymogenic right ventricular dysplasia 2.
Two morphologic variants of ARVD have been reported: fatty and fibrofatty.
The fatty form is characterized by almost complete replacement of the myocardium without thinning of the ventricular wall, and it occurs exclusively in the right ventricle.
The fibro-fatty variant is associated with significant thinning of the right ventricular wall, and the left ventricular myocardial wall may also be involved 1-2.
Both idiopathic and familial etiologies have been proposed (see epidemiology above) 2.
As the name implies it classically involves the right ventricle although on autopsy studies a sizeable number of cases also show a degree of left ventricular involvement.
Plain films are non specific and can be often normal. May show evidence of right ventricular dilatation (best seen on a lateral view)
The right ventricle is often dilated and hypokinetic
Most sensitive imaging modality for diagnosis although image interpretation can still be difficult due to a degree of RV wall focal fatty infiltration (high signal on T1) in normal individuals 3. Classically demonstrates fibro-fatty diposition in right ventricular free wall as well as morphological features of right ventricular dilation. The ventricular wall may be thinned as a result. The left ventricle is usually spared (except in a very small proportion of cases 6). SSFP sequences may provide additional information on functional wall impairment.
Other associated features include
- right ventricular aneurysm formation
- diffuse right ventricular wall thinning resulting in severe global dilatation
- segmental hypokinesia.
May show right ventricular dilation and fatty low attenuation to the right ventricular wall.
Treatment and prognosis
ARVD is a progressive disease and will probably lead to right ventricular failure in the long term unless sudden cardiac death occurs beforehand.
The four therapeutic options in patients with ARVD include antiarrhythmic agents, catheter ablation, implantable cardioverter defibrillators, and surgery.
Imaging differential considerations include