Table 1.

The ‘Padua criteria’ for diagnosis of arrhythmogenic cardiomyopathy

Category	Right ventricle	Left ventricle
1. Morphofunctional ventricular abnormalities	By echocardiography, CMR or angiography: Major Regional RV akinesia, dyskinesia or bulging plus one of the following: Global RV dilatation (increase in RV EDV according to the imaging test-specific nomograms). Global RV systolic dysfunction (reduction in RV EF according to the imaging test-specific nomograms). Minor Regional RV akinesia, dyskinesia or aneurysm of RV free wall.	By echocardiography, CMR or angiography: Minor Global LV systolic dysfunction (depression of LV EF or reduction of echocardiographic global longitudinal strain), with or without LV dilatation (increase in LV EDV according to the imaging test-specific nomograms for age, sex and BSA). Minor Regional LV hypokinesia or akinesia of LV free wall, septum or both.
2. Structural myocardial abnormalities	By CE-CMR: Major Transmural LGE (stria pattern) of ≥1 RV region(s) (inlet, outlet and apex in two orthogonal views). By EMB (limited indications): Major Fibrous replacement of the myocardium in ≥1 sample, with or without fatty tissue.	By CE-CMR: Major LV LGE (stria pattern) of ≥1 Bull’s eye segment(s) (in two orthogonal views) of the free wall (subepicardial or mid-myocardial), septum or both (excluding septal junctional LGE).
3. Repolarisation abnormalities	Major Inverted T-waves in right precordial leads (V1, V2 and V3) or beyond in individuals with complete pubertal development (in the absence of complete RBBB). Minor Inverted T-waves in leads V1 and V2 in individuals with complete pubertal development (in the absence of complete RBBB). Inverted T-waves in V1, V2, V3 and V4 in individuals with complete pubertal development in the presence of complete RBBB.	Minor Inverted T-waves in left precordial leads (V4–V6) (in the absence of complete LBBB).
4. Depolarisation abnormalities	Minor Epsilon wave (reproducible low-amplitude signals between end of QRS complex and onset of the T-wave) in the right precordial leads (V1–V3). Terminal activation duration of QRS ≥55 ms measured from the nadir of the S-wave to the end of the QRS, including R’, in V1, V2 or V3 (in the absence of complete RBBB).	Minor Low QRS voltages (<0.5 mV peak to peak) in limb leads (in the absence of obesity, emphysema or pericardial effusion).
5. Ventricular arrhythmias	Major Frequent ventricular extrasystoles (>500 per 24 hours), non-sustained or sustained ventricular tachycardia of LBBB morphology. Minor Frequent ventricular extrasystoles (>500 per 24 hours), non-sustained or sustained ventricular tachycardia of LBBB morphology with inferior axis (‘RVOT pattern’).	Minor Frequent ventricular extrasystoles (>500 per 24 hours), non-sustained or sustained ventricular tachycardia with an RBBB morphology (excluding the ‘fascicular pattern’).
6. Family history/genetics	Major ACM confirmed in a first-degree relative who meets the diagnostic criteria. ACM confirmed pathologically at autopsy or surgery in a first-degree relative. Identification of a pathogenic or likely pathogenetic ACM mutation in the patient under evaluation. Minor History of ACM in a first-degree relative in whom it is not possible or practical to determine whether the family member meets the diagnostic criteria. Premature sudden death (<35 years of age) due to suspected ACM in a first-degree relative. ACM confirmed pathologically or by diagnostic criteria in a second-degree relative.

ACM, arrhythmogenic cardiomyopathy; BSA, body surface area; CE-CMR, contrast enhanced-cardiac magnetic resonance; EDV, end diastolic volume; EF, ejection fraction; EMB, endomyocardial biopsy; LBBB, left bundle branch block; LGE, late gadolinium enhancement; LV, left ventricle; RBBB, right bundle branch block; RV, right ventricle; RVOT, right ventricular outflow tract.