Table 1.

2010 Task Force diagnostic criteria for ACM

	Major criteria	Minor criteria
RV systolic function and structure	By 2D echo:	By 2D echo:
	► Regional RV akinesia, dyskinesia or aneurysm and one of the following (end diastole): PLAX RVOT ≥ 32 mm, PLAX‐RVOT/BSA ≥ 19 mm/m2 PSAX RVOT ≥ 36 mm, PSAX‐RVOT/BSA ≥ 21 mm/m2 Or fractional area change ≤33%	Regional RV akinesia, dyskinesia or and 1 of the following (end diastole) PLAX RVOT ≥29 to <32 mm, PLAX‐RVOT/BSA ≥ 16 to <19 mm/m2 PSAX RVOT ≥32 to <36 mm, PSAX‐RVOT/BSA ≥ 18 to <21 mm/m2 Or fractional area change >33% to ≤40%
	By MRI:	By MRI
	► Regional RV akinesia, dyskinesia or dyssynchronous RV contraction and 1 of following: Ratio of RV end diastolic volume to BSA ≥ 110 ml/m2 (male) or ≥100 ml/m2 (female) (or RV EF ≤ 40%)	Regional RV akinesia, dyskinesia or dyssynchronous RV contraction and 1 of the following: Ratio of RV end‐diastolic volume to BSA ≥ 100 to <110 ml/m2 (male) or ≥90 to <100 ml/m2 (female) or RV EF > 40% to ≤ 45%
	By RV angiography:
	Regional RV akinesia, dyskinesia or aneurysm
Tissue characterization	Residual myocytes <60% by morphometric analysis (or <50% if estimated) with fibrous replacement of the RV free wall myocardium in ≥1 sample, with or without fatty replacement of tissue on EMB	Residual myocytes 60% to 75% by morphometric analysis (or 50% to 65% if estimated), with fibrous replacement of the RV free wall myocardium in ≥1 sample, with or without fatty replacement of tissue on EMB
Repolarization’ abnormality	► Inverted T waves in right precordial leads (V1–3) or beyond in individuals >14 years of age (in the absence of complete right bundle ‐ branch block QRS ≥ 120 ms	Inverted T waves in leads V1 and V2 in individuals >14 years of age (in the absence of complete right bundle branch block) or in V4–6 or inverted T waves in leads V1–V4 in individuals >14 years of age in the presence of complete right bundle branch block
Depolarization abnormality	► Epsilon waves (reproducible low‐amplitude signals between the end of QRS complex to onset of the T wave) in the right precordial leads (V1–3)	Late potential by SAECG in ≥1 of 3 parameters in the absence of a QRS duration of ≥110 ms on the standard ECG; filtered QRS duration ≥114 ms; Duration of terminal QRS < 40 μV (low amplitude signal duration) or ≥38 ms; Root‐mean‐square voltage of terminal 40 ms ≤ 20 μV; Terminal activation duration of QRS ≥ 55 ms measured from the nadir of the S wave to the end of QRS, including R′, in V1–3, in the absence of complete right bundle‐branch block
Arrhythmias	Nonsustained or sustained ventricular tachycardia of left bundle‐branch morphology with superior axis (negative or indeterminate QRS in leads II, III and aVF and positive in lead aVL)	Nonsustained or sustained ventricular tachycardia of RV outflow configuration, left bundle‐branch morphology with inferior axis (positive QRS in leads II, III, and aVF and negative in lead aVL) ► or >500 ventricular extrasystoles per 24 h (Holter)
Family history	ACM who meets Task Force criteria or confirmed pathologically in a first degree relative pathogenic mutation categorized as associated or probably associated with ACM in the patient under evaluation	History of ACM in a first degree relative or premature sudden death (<35 years of age) due to suspected ACM in a first degree relative or ACM confirmed pathologically or by current Task Force Criteria in second‐degree relative

Note: Adapted from References 3, 4 with minor modifications. Definite diagnosis of ACM: 2 major, or 1 major and 2 minor, or 4 minor criteria, borderline diagnosis: 1 major and 1 minor, or 3 minor criteria, possible diagnosis: 1 major or 2 minor criteria from different categories. ► criteria that were present in our patient.

Abbreviations: ACM, arrhythmogenic cardiomyopathy; BSA, body surface area; ECG, electrocardiogram; EMB, endomyocardial biopsy; LV, left ventricle; MRI; magnetic resonance imaging; PLAX, parasternal long axis; PSAX, parasternal short axis; RV, right ventricular; RVOT, right ventricular outflow tract; SAECG, signal averaged ECG.