Table 2.

Comparison between the 2020 International “Padua” Criteria and 2023 European Task Force criteria for diagnosis of Arrhythmogenic Cardiomyopathy.

Category	2020 International criteria	2023 European Task Force criteria
1. Global or regional dysfunction and structural alteration	RV phenotype	RV phenotype
	Major	Major
	By 2D echocardiogram, CMR, or angiography:	• Regional RV akinesia, dyskinesia, or aneurysm plus one of the following:
	• Regional RV akinesia, dyskinesia, or bulging plus 1 of the following:	- global RV dilatation (increase of RV EDV according to the imaging test specific nomograms for age, sex and BSA)
	- global RV dilatation (increase of RV EDV according to the imaging test specific nomograms for age, sex, and BSA)	or
	or	- global RV systolic dysfunction (reduction of RV EF according to the imaging test specific nomograms for age and sex)
	- global RV systolic dysfunction (reduction of RV EF according to the imaging test specific nomograms for age and sex)	Minor
	Minor	• Regional RV akinesia, dyskinesia or aneurysm of RV free wall
	By 2D echocardiogram, CMR, or angiography:
	• Regional RV akinesia, dyskinesia or aneurysm of RV free wall
	LV phenotype	LV phenotype
	Minor	Minor
	By echocardiography, CMR or angiography:	• Global LV systolic dysfunction, with or without LV dilatation (increase of LV EDV according to the imaging test specific nomograms for age, sex, and BSA)
	• Global LV systolic dysfunction (depression of LV EF or reduction of echocardiographic global longitudinal strain), with or without LV dilatation (increase of 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. Tissue characterization	RV phenotype	RV phenotype
	Major	Major
	By CE-CMR:	• Fibrous replacement of the myocardium in $\ge$1 sample, with or without fatty tissue, at histology
	• Transmural LGE (stria pattern) of $\ge$1 RV region(s) (inlet, outlet, and apex in 2 orthogonal views)	Minor
	Major	• Unequivocal RV LGE (confirmed in 2 orthogonal views) in $\ge$1 RV region(s) (excluding tricuspid valve)
	By EMB (limited indications):
	• Fibrous replacement of the myocardium in $\ge$1 sample, with or without fatty tissue
	LV phenotype	LV phenotype
	Major	Major
	By CE-CMR	• “Ring-like” LV LGE (subepicardial or midmyocardial stria pattern) of $\ge$3 segments (confirmed in 2 orthogonal views)
	• LV LGE (stria pattern) of $\ge$1 Bull’s Eye segment(s) (in 2 orthogonal views) of the free wall (subepicardial or midmyocardial), septum, or both (excluding septal junctional LGE)	Minor
		• LV LGE (subepicardial or midmyocardial stria pattern) of 1 or 2 Bull’s Eye segment(s) (in 2 orthogonal views) of the free wall, septum, or both (excluding patchy, focal or septal junctional LGE)
3. Repolarization abnormalities	RV phenotype	RV phenotype
	Major	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)	• Negative T waves in right precordial leads (V1, V2, and V3) or beyond in individuals $\ge$14-year-old (in the absence of complete RBBB and not preceded by J-point/ST-segment elevation)
	Minor	Minor
	• Inverted T waves in leads V1 and V2 in individuals with completed pubertal development (in the absence of complete RBBB)	• Negative T waves in leads V1 and V2 in males $\ge$14-year-old (in the absence of RBBB and not preceded by J-point/ST-segment elevation)
	• Inverted T waves in V1, V2, V3 and V4 in individuals with completed pubertal development in the presence of complete RBBB	• Negative T waves beyond V3 in the presence of complete RBBB
		• Negative T waves beyond V3 in individuals 14-year-old
	LV phenotype	LV phenotype
	Minor	Minor
	• Inverted T waves in left precordial leads (V4–V6) (in the absence of complete LBBB)	• Negative T waves in left precordial leads (V4–V6) (in the absence of complete LBBB)
4. Depolarization and conduction abnormalities	RV phenotype	RV phenotype
	Minor	Minor
	• Epsilon wave (reproducible low-amplitude signals between end of QRS complex to onset of the T wave) in the right precordial leads (V1 to V3)	• Epsilon wave (reproducible low-amplitude signals between end of QRS complex to onset of the T wave) in the right precordial leads (V1 to V3)
	• Terminal activation duration of QRS $\ge$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)	• Terminal activation duration of QRS $\ge$55 ms measured from the nadir of the S wave to the end of the QRS, including R’, in V1, V2, or V3 (in the absence of complete RBBB)
	LV Phenotype	LV Phenotype
	Minor	Major
	• Low QRS voltages (0.5 mV peak to peak) in limb leads (in the absence of obesity, emphysema, or pericardial effusion)	• Low QRS voltages (0.5 mV peak to peak) in all limbs leads in the absence of other causes (e.g., cardiac amyloidosis, obesity, emphysema, or pericardial effusion)
5. Arrhythmias	RV Phenotype	RV Phenotype
	Major	Major
	• Frequent ventricular extrasystoles ($>$500 per 24 h), non-sustained or sustained ventricular tachycardia of LBBB morphology	• Frequent ventricular extrasystoles ($>$500 per 24 h), non-sustained or sustained ventricular tachycardia of LBBB morphology with non-inferior axis
	Minor	Minor
	• Frequent ventricular extrasystoles ($>$500 per 24 h), non-sustained or sustained ventricular tachycardia of LBBB morphology with inferior axis (“RVOT pattern”)	• Frequent ventricular extrasystoles ($>$500 per 24 h), non-sustained or sustained ventricular tachycardia of LBBB morphology with inferior axis (“RVOT pattern”)
		• History of cardiac arrest due to ventricular fibrillation or sustained ventricular tachycardia of unknown morphology
	LV phenotype	LV phenotype
	Minor	Minor
	• Frequent ventricular extrasystoles ($>$500 per 24 h), non-sustained or sustained ventricular tachycardia with a RBBB morphology (excluding the “fascicular pattern”)	• Frequent ($>$500 per 24 h) or exercise-induced ventricular extrasystoles with a RBBB morphology or multiple RBBB morphologies (excluding the “fascicular pattern”)
		• Non-sustained or sustained ventricular tachycardia with a RBBB morphology (excluding the “fascicular pattern”)
		• History of cardiac arrest due to ventricular fibrillation or sustained ventricular tachycardia of unknown morphology
6. Family history/genetics	RV/LV phenotype	RV/LV phenotype
	Major	Major
	• Identification of a pathogenic or likely pathogenetic ACM mutation in the patient under evaluation	• Identification of a pathogenic ACM-gene variant in the patient under evaluation
	• ACM confirmed in a first-degree relative who meets diagnostic criteria	• ACM confirmed in a first-degree relative who meets diagnostic criteria
	• ACM confirmed pathologically at autopsy or surgery in a first-degree relative	• ACM confirmed pathologically at autopsy or surgery in a first-degree relative
	Minor	Minor
	• History of ACM in a first-degree relative in whom it is not possible or practical to determine whether the family member meets diagnostic criteria	• Identification of a likely-pathogenic ACM-gene variant in the patient under evaluation
	• Premature sudden death (35 years of age) due to suspected ACM in a first-degree relative	• History of ACM in a first-degree relative in whom it is not possible or practical to determine whether the family member meets diagnostic criteria
	• ACM confirmed pathologically or by diagnostic criteria in second-degree relative	• Premature sudden death (35 years of age) due to suspected ACM in a first-degree relative
		• ACM confirmed pathologically or by diagnostic criteria in 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; 2D, 2-dimensional.