Arrhythmogenic right ventricular cardiomyopathy: From genetics to diagnostic and therapeutic challenges

Table 1 Revised arrhythmogenic right ventricular cardiomyopathy diagnostic criteria (modified from Marcus et al[33])

	Major criteria	Minor criteria
RV systolic function and structure	By 2D echo: Regional RV akinesia, dyskinesia or aneurysm and one of the following (end diastole): PLAX RVOT ≥ 32 mm, PSAX RVOT ≥ 36 mm, Or fractional area change ≤ 33%	By 2D echo: Regional RV akinesia, dyskinesia or aneurysm and 1 of the following (end diastole): PLAX RVOT ≥ 29 to < 32 mm, PSAX RVOT ≥ 32 to < 36 mm, Or fractional area change > 33% to ≤ 40%
	By MRI: Regional RV akinesia, dyskinesia or aneurysm or dyssynchronous RV contraction and 1 of following: Ratio of RV end-diastolic volume to BSA ≥ 110 mL/m2 or ≥ 100 mL/m2 (or RV EF ≤ 40%)	By MRI: Regional RV akinesia, dyskinesia or aneurysm 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 > 40% to ≤ 45 %
	By RV angiography: Regional RV akinesia, dyskinesia or aneurysm	By RV angiography: Regional RV akinesia, dyskinesia or aneurysm
Tissue characterization	Residual myocytes < 60% by morphometric analysis 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% (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 yr 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 individuals > 14 yr of age in the presence of complete right bundle branch block
Depolarization abnormality	Epsilon waves 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 mV or ≥ 38 μs; 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
Arrhythmias	Nonsustained or sustained ventricular tachycardia of left bundle branch morphology with superior axis Frequent ventricular extrasystoles (> 1000 per 24 h) (Holter)	Nonsustained or sustained ventricular tachycardia of RV outflow configuration, left bundle branch morphology with inferior axis or > 500 ventricular extrasystoles per 24 h (Holter)
Familial history	ARVC confirmed pathologically in the first degree or identification of a pathogenic mutation categorized as associated or probably associated with ARVC	History of ARVC in a first degree relative or premature sudden death (< 35 yr of age) due to suspected ARVC or ARVC confirmed pathologically or by current Task Force Criteria in second-degree relative

LV: Left ventricle; RV: Right ventricular; ARVC: Arrhythmogenic right ventricular cardiomyopathy; PLAX: Parasternal long axis; PSAX: Parasternal short axis; RVOT: Right ventricle outflow tract; ECG: Electrocardiogram; EMB: Endomyocardial biopsy; MRI; Magnetic resonance imaging; SAECG: Signal averaged ECG; BSA: body surface area.