The 2020 International Criteria for Arrhythmogenic Cardiomyopathy, commonly known by the shorthand Padua criteria, follow a two-step approach for diagnosing arrhythmogenic cardiomyopathy (ACM). It includes the identification of major and minor criteria that are satisfied for both left and right ventricle and the classification of ACM phenotype under one of three categories ⁵:

• classic arrhythmogenic right ventricular cardiomyopathy (ARVC)

• biventricular disease

• arrhythmogenic left ventricular cardiomyopathy (ALVC)

Classification

Arrhythmogenic left ventricular cardiomyopathy 

Major criteria

• structural myocardial abnormality

  • late gadolinium enhancement (stria pattern) of the left ventricle in more than one Bull’s eye segment of the free wall, septum or both

• genotype 

  • identification of a known ACM causative mutation in a patient 

  • presence of a first-degree relative who fulfills the diagnostic criteria or has a confirmed ACM diagnosis following surgery or autopsy

Minor criteria

• morpho-functional ventricular abnormalities

  • regional left ventricular hypokinesia or akinesia 

  • global systolic dysfunction of left ventricle with or without left ventricular dilatation

• depolarization abnormalities

  • presence of low voltage QRS complexes in limb leads

• repolarization abnormalities

  • presence of inverted T waves in leads V4- V6

• ventricular arrhythmia

  • presence of sustained or non-sustained ventricular tachycardia, and ventricular extrasystoles 

• genotype 

  • confirmed ACM in a second- degree relative

  • sudden death in a first degree relative less than 35 years of age due to suspected ACM

  • history of ACM in a first degree relative who does not meet the diagnostic criteria  

Arrhythmogenic right ventricular cardiomyopathy

Major criteria

• global or regional dysfunction and structural alteration 

  • regional right ventricular dyskinesia, akinesia or bulging and one of either global right ventricular dilatation or global right ventricular systolic dysfunction visualized on cardiac magnetic resonance, 2D echocardiogram or angiography 

• tissue characterization 

  • transmural late gadolinium enhancement (stria pattern) visualized in more than one region of right ventricle 

  • fibrous replacement of myocardium seen in one or more samples 

• abnormalities in repolarization 

  • inverted T waves in leads V1-3 in the absence of complete right bundle branch block 

• arrhythmia 

  • more than 500 ventricular extrasystoles in 24hrs, sustained or non-sustained ventricular tachycardia in left bundle branch block morphology 

• genotype and family history 

  • presence of an ACM causative mutation in the patient 

  • presence of a first degree relative who fulfills the diagnostic criteria or has ACM confirmed during surgery or autopsy

Minor criteria

• global or regional dysfunction and structural alteration 

  • right ventricular free wall aneurysm, regional right ventricular dyskinesia or akinesia visualized on 2D echocardiogram, angiography or cardiac magnetic resonance

• abnormalities in repolarization

  • inverted T waves in leads v1-2 in the absence of complete right bundle branch block 

  • inverted T waves in leads V1-4 in the presence of complete right bundle branch block 

• abnormalities in depolarization and conduction 

  • presence of epsilon waves in leads V1-3

  • terminal activation duration of more than 55 ms in QRS complex when measured from the nadir of S wave to the end of the QRS complex in leads V1-3 in the absence of complete right bundle branch block

• arrhythmia

  • more than 500 ventricular extrasystoles in 24hrs, sustained or non-sustained ventricular tachycardia in RVOT pattern

• genotype and family history

  • confirmed arrhythmogenic cardiomyopathy in a second degree relative 

  • premature sudden death in a first degree relative less than 35 years of age suspected to be due to arrhythmogenic cardiomyopathy 

  • first degree relative with arrhythmogenic cardiomyopathy who does not meet the diagnostic criteria

Interpretation

Diagnosis of ALVC requires the presence of a genetic mutation in addition to phenotypic features. 

The diagnosis of ARVC can fall into three categories:

• definite ARVC: 2 major or 1 major plus 2 minor or 4 minor right ventricular diagnostic criteria in different categories

• borderline ARVC: 1 major plus 1 minor or 3 minor criteria under different categories

• possible ARVC: 1 major or 2 minor criteria

Patients with biventricular ACM fulfill the criteria for both LV and RV phenotype.