5th July 2026

Diagnosis and Diagnostic Criteria

Diagnostic Criteria

One of the most common underdiagnosed causes of sudden cardiac death in young people, ARVC is diagnosed with either two major criteria, one major and two minor criteria, or four minor criteria, summarised in Table 1 below.

Table 1. Diagnostic Criteria of AVRC, adapted from Escardio.org/Journals/E-journal-of-cardiology-practice/Volume-1/Arrhythmogenic-right-ventricualr-cardiomyopathy-Title-Arrhythmogenic-right-ve

The standard of reference for diagnosis of ARVC is the histologic demonstration of transmural fibrofatty replacement of the right ventricular myocardium at autopsy or surgery, with criteria of greater than 3% fat and less than 40% fibrous tissue replacing the myocardial muscle.

Signs and symptoms 

• Palpitations and syncope: most frequently experienced symptoms in patients with ACM. These are often triggered by exercise, and related to ventricular arrhythmias which include premature ventricular complexes, sustained or non-sustained ventricular tachycardia (NSVT) and ventricular fibrillation.

• Sudden cardiac death (SCD) can be the first presenting feature in patients subsequently diagnosed with ACM. Over half of affected individuals (estimated at 60%) may be asymptomatic prior to mortality. 
• Progressive heart failure affecting the right, left or both ventricles, is also observed in some patients and is a common indication for heart transplant. 
• Angina, fatigue, and dyspnoea may also be reported.

Clinical examination may be normal, or signs that may be elicited include: 

• split S2
• S3 gallop during rapid ventricular phase of diastole, indicating ventricular dilatation
• S4

Investigations

Primary investigations for patients with ARVC include:

• Bloods: BNP elevation, FBC, U+Es, thyroid function, LFTs and troponin
• ECG: 
  • May have T wave inversion in leads V1-V3 suggests abnormal repolarisation in the right ventricle. 
  • Epsilon waves represent delayed depolarisation in the right ventricular outflow tract. They are characterised by small positive deflections at the end of QRS complexes in leads V1-V4 (figure 1). 
  • Ventricular ectopy and recurrent monomorphic VT with an LBBB pattern indicate abnormal ventricular electrical activity. 
  • Late potentials on a signal-averaged ECG reflect delayed conduction, all pointing to electrical instability in ARVC.
• Echocardiogram: may show a right ventricular dilatation or demonstrate aneurysmal projections from the right ventricular wall.

Other investigations to consider include:

• Ambulatory monitoring
  • Represents a major criterion in detecting frequent ventricular extrasystoles (>500) across 24 hours, non-sustained or sustained ventricular tachycardia of left bundle branch block morphology. 
• Cardiac MRI: 
  • On T1-weighted images, the right ventricular free wall often shows increased signal intensity due to the replacement of normal heart muscle with fatty or fibrous tissue. Thinning refers to the reduction in thickness of the right ventricular free wall, which can be a result of structural damage or atrophy. Akinesis may also be a result of this due to poor movement, and over time, this can be the predisposing cause of aneurysms, which can also be detected on MRI. In particular, ARVC may affect the triangle of dysplasia particularly, including the right ventricular outflow tract, the apex, and the inflow tract.
• Cardiac catheterisation
  • May show right ventricular enlargement or right ventricular wall motion abnormalities.
• Exercise stress testing
  • Might demonstrate any exercise-related ventricular tachyarrhythmias
• Endomyocardial biopsy
  • Used to detect fibro-fatty replacement of myocardium.