Table 1.

European Task Force criteria for diagnosis of arrhythmogenic cardiomyopathy.

Category	Criteria for RV involvement	Criteria for LV involvement
1. Morpho-functional ventricular abnormalities	Major	Minor
	• Regional RV akinesia, dyskinesia, or aneurysm plus one of the following:	• 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 RV dilatation (increase of RV EDV according to the imaging test specific nomograms for age, sex and BSA)
	or
	- global RV systolic dysfunction (reduction of RV EF according to the imaging test specific nomograms for age and sex)
	Minor
	• Regional RV akinesia, dyskinesia or aneurysm of RV free wall
2. Structural myocardial abnormalities	Major	Major
	• Fibrous replacement of the myocardium in $\ge$1 sample, with or without fatty tissue, at histology	• “Ring-like” LV LGE (subepicardial or midmyocardial stria pattern) of $\ge$3 segments (confirmed in 2 orthogonal views)
	Minor	Minor
	• Unequivocal RV LGE (confirmed in 2 orthogonal views) in $\ge$1 RV region(s) (excluding tricuspid valve)	• 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. ECG repolarization abnormalities	Major	Minor
	• 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)	• Negative T waves in left precordial leads (V4–V6) (in the absence of complete LBBB)
	Minor
	• 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)
	• Negative T waves beyond V3 in the presence of complete RBBB
	• Negative T waves beyond V3 in individuals 14-year-old
4. ECG depolarization and conduction abnormalities	Minor	Major
	• 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)	• 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)
	• Terminal activation duration of QRS $\ge$55 ms measured from the nadir of the S wave to the end of the QRS, including R’, in V1, V2, or V3 (in the absence of complete RBBB)
5. Arrhythmias	Major	Minor
	• Frequent ventricular extrasystoles ($>$500 per 24 h), non-sustained or sustained ventricular tachycardia of LBBB morphology with non-inferior axis	• Frequent ($>$500 per 24 h) or exercise-induced ventricular extrasystoles with a RBBB morphology or multiple RBBB morphologies (excluding the “fascicular pattern”)
	Minor	• Non-sustained or sustained ventricular tachycardia with a RBBB morphology (excluding the “fascicular pattern”)
	• Frequent ventricular extrasystoles ($>$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
	• History of cardiac arrest due to ventricular fibrillation or sustained ventricular tachycardia of unknown morphology
6. Family history/genetics	Major
	• 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 pathologically at autopsy or surgery in a first-degree relative
	Minor
	• Identification of a likely-pathogenic ACM-gene variant in the patient under evaluation
	• 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
	• 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; ECG, electrocardiogram; EDV, end diastolic volume; EF, ejection fraction; 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. Adapted from [13].