rrhythmogenic right ventricular dysplasia (ARVD, now also called ARVC for arrhythmogenic right ventricular cardiomyopathy) is an inherited cardiomyopathy. It is inherited in an autosomal dominant pattern with variable penetrance. It can be found in 1:1000 of the population, and is a significant cause of sudden cardiac death in young athletes.
The normal myocardium of the right ventricle becomes replaced by a chaotic mix of fibrous tissue and fat interspersed within myocardium. The myocardium becomes extremely thinned. The left ventricular may also be involved, but often to a lesser extent. These pathologic changes usually become evident by the time the patient is 20-30 years old.
The effect of these morphologic changes is right ventricular failure and rhythm abnormalities. Ventricular tachycardia and ventricular fibrillation is common, and unfortunately can result in sudden cardiac death (SCD). Structural remodelling of the myocardial wall progresses with the course of the disease, and this generates more and more foci for initiating arrhythmias.
The diagnosis can be challenging due to nonspecific clinical features. It is important to gather structural, functional, and electrophysiologic information about the patient’s heart to make the diagnosis. The first diagnostic criteria were laid out in 1994 by the International Task Force, and revised in 2010. However, it is usually arrhythmia (especially ventricular tachycardia), that first brings the healthy patient medical attention.
Simplified diagnostic criteria of ARVD (2 required). Adopted from Circulation 2010;121:1533.
- Structural. Regional RV akinesia, dyskinesia, or aneurysm with either dilated RVOT or decreased EF by echo, MRI, or angiography.
- Tissue. Residual myocytes <50% of RV free wall by biopsy.
- Repolarization abnormalities. Inverted T waves in the right precordial leads (V1-v#) in the absence of complete RBBB
- Depolarization/conduction abnormalities. Epsilon wave in the right precordial leads (V1 – V3)
- Arrhythmias. Nonsustained or sustained ventricular tachycardia of LBBB morphology with superior axis.
- Family history. First degree relative diagnosed with ARVD.
The ECG changes in ARVD include:
- Epsilon wave (most specific finding, seen in 30% of patients). From Slow RV.
- T wave inversions in V1-3 (85% of patients)
- Prolonged S-wave upstroke of 55ms in V1-3 (95% of patients)