Most-often inherited disease of the myocardium
resulting in cardiomyopathy and risk of sudden death in otherwise healthy
Arrhythmogenic Right Ventricular Cardiomyopathy; ARVC.
Rare. Predominance in males. Arrhythmogenic right
ventricular dysplasia (ARVD) is estimated to account for up to 5% of
unexpected sudden deaths in individuals younger than 65 years and 3 to 4%
of sudden deaths occurring during sports. The prevalence is unknown, and
estimates range from 1.5:1000 to 4.5:1000 in the general population.
Autosomal dominant, with mutations mapped to
chromosome 14. However, depending on the gene/ chromosome involved, eight
different types of ARVD have been described. Type 1 is the most common form.
Autosomal recessive and sporadic forms have been described.
Abnormal development of the right ventricle
results in fibrous and fatty deposits in the free wall of the right
ventricular myocardium. The subepicardial and mediomural layers are
predominately affected; the subendocardial area may be preserved. Uhl
anomaly is a severe form of ARVD in which the myocardium is severely
dysplastic and the epicardium and endocardium are closely applied, resulting
in the so-called “parchment ventricle.” The left ventricle may be involved
in severe forms. The interventricular septum usually is preserved. Two
pathologic types of ARVD have been described.
1. The fibrofatty form is characterized by a mixture of fat and fibrous tissue,
myocardial thinning, and atrophy of the myocytes. The degeneration typically
affects a triangular area (so-called “triangle of dysplasia”), which
comprises the right ventricular infundibulum, the lateral apical region, and
the right ventricular outflow tract. In the majority of cases, the
myocardium shows lymphocytic infiltrates, which may extend to left
ventricular areas. Approximately half of patients show a right ventricular
aneurysm at autopsy.
2. The second form is the fatty form, in which the right ventricular myocardium is
replaced partly or almost entirely by adipose tissue. Lymphocytic
infiltrates most often are missing, and left ventricular involvement is
The main clinical consequences arising from these degenerative changes are
various forms of arrhythmias caused by abnormalities in depolarization,
repolarization, and conduction.
Based on ECG findings (e.g., T-wave inversion
on right-sided chest leads, right bundle branch block at rest, and isolated
QRS prolongation in leads V1-V3). One of the main findings on
echocardiography is dilatation of the right ventricle. Fatty infiltration of
the myocardium can often be seen. At a later stage, sacculations or
aneurysms of the right ventricular free wall in combination with right
ventricular thinning and wall-motion abnormalities can be found.
Endomyocardial biopsy and MRI may be useful to confirm the diagnosis.
Valvular heart disease, active myocarditis, metabolic cardiomyopathy, and
coronary artery disease must be excluded. Based on the classification and
the criteria of the European Society of Cardiology and the ISFC Working
Group on Cardiomyopathies and Dysplasia, the diagnosis of ARVD is confirmed
if two major criteria, or one major plus two minor criteria, ...