Is cardiac MRI an effective test for arrhythmogenic right ventricular cardiomyopathy diagnosis?

Table 1 Task force criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy[19]

1 Global and/or regional dysfunction and structural alterations (detected by echocardiography, angiography, magnetic resonance imaging, or radionuclide scintigraphy)

Major: Severe dilatation and reduction of right ventricular ejection fraction with no (or only mild) left ventricular impairment. Localized right ventricular aneurysms (akinetic or dyskinetic areas with diastolic bulging). Severe segmental dilatation of the right ventricle

Minor: Mild global right ventricular dilatation and/or ejection fraction reduction with normal left ventricle Mild segmental dilatation of the right ventricle Regional right ventricular hypokinesia

2 Tissue characterization of wall

Major: Fibro-fatty replacement of myocardium on endomyocardial biopsy

3 Repolarisation Abnormalities

Minor: Inverted T waves in right precordial leads (V2 and V3) in people aged > 12 yr, in absence of right bundle branch block

4 Depolarization/conduction abnormalities

Major: Epsilon waves or localized prolongation (> 110 ms) of the QRS complex in right precordial leads (V1-V3)

Minor: Late potentials (signal-averaged ECG)

5 Arrhythmias

Minor: Left bundle branch block type ventricular tachycardia (sustained and non-sustained) by ECG, Holter or exercise testing. Frequent ventricular extra-systoles (> 1000/24 h) by Holter

6 Family history

Major: Familial disease confirmed at necropsy or surgery

Minor: Family history of premature sudden death (< 35 yr) due to suspected right ventricular dysplasia. Familial history (clinical diagnosis based on present criteria)

The diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC) would be fulfilled in the presence of 2 major criteria or 1 major plus 2 minor or 4 minor criteria from the different groups. ECG: Electrocardiogram.

Table 2 Revised task force criteria for imaging[5]

Major

By 2D echo:

Regional RV akinesia, dyskinesia or aneurysm and one of the following (end diastole):

1 Parasternal long axis view RVOT (PLAX) ≥ 32 mm (corrected for body size (PLAX/BSA) ≥ 19 mm/m2)

2 Parasternal short axis view RVOT (PSAX) ≥ 36 mm (corrected for body size (PSAX/BSA) ≥ 21 mm/m2)

3 Or fractional area change (FAC) ≤ 33%

By MRI:

Regional RV akinesia or dyskinesia or dyssynchronous RV contraction and one of the following:

1 Right ventricular end diastolic volume (RVEDV/BSA) ≥ 110 mL/m2 (male) or ≥ 100 mL/m2 (female)

2 Or RVEF ≤ 40%

By RV angiography:

Regional RV akinesia, dyskinesia or aneurysm

Minor

By 2D echo Regional RV akinesia or dyskinesia and one of the following (end diastole):

1 Parasternal long axis view RVOT (PLAX) ≥ 29 - < 32 mm (corrected for body size (PLAX/BSA) ≥ 16 - < 19 mm/m2)

2 Parasternal short axis view RVOT (PSAX) ≥ 32 - < 36 mm (corrected for body size(PSAX/BSA) ≥ 18 - < 21 mm/m2)

3 Or FAC > 33% - ≤ 40%

By MRI Regional RV akinesia or dyskinesia or dyssynchronous RV contraction and one of the following:

1 Right ventricular end diastolic volume/BSA ≥ 100 - < 110 mL/m2 (male) or ≥ 90 - < 100 mL/m2 (female)

2 RVEF > 40% - ≤ 45%

RVEF: Right ventricular ejection fraction; RVOT: Right ventricular outflow tract; FAC: Fractional area change.

Table 3 Study population

Time period	May 2006-Feb 2010
Total No. of patients referred	121
Total No. of patients scanned	114
Age range	16 to 83
16-20	7 (6%)
21-30	19 (17%)
31-40	25 (22%)
41-50	28 (24%)
51-60	21 (18%)
61-70	10 (9%)
71-80	3 (3%)
81-90	1 (1%)
Males	63 (55%)
Females	51 (45%)
Referrals
Teaching Hospitals	96 (84%)
District General Hospitals	18 (16%)
Reasons for referral
Arrhythmias	34 (30%)
Family history of sudden death	23 (20%)
Others	57 (50%)
Others
Abnormal RV in echo	22 (19%)
Brugada syndrome	8 (7%)
Syncope	8 (7%)
Palpitations	6 (5%)
Dilated cardiomyopathy in echo	4 (3.5%)
Frequent ectopics	4 (3.5%)
SVT	3 (3%)
Abnormal LV	1 (1%)
Cardiac arrest	1 (1%)

RV: Right ventricle; LV: Left ventricle.

Table 4 Results

RV abnormalities related to ARVC	19 (17%)
Major	4 (4%)
Minor	13 (11%)
Non specific	2 (2%)
Other diagnoses	95 (83%)
Normal	63 (55%)
Dilated cardiomyopathy	8 (7%)
Left to right shunt	1 (1%)
RV infarction	1 (1%)
LV infarction	1 (1%)
Other mild abnormalities	21 (18%)
Clinically proven ARVC	5 (4%)
cMR major	3
cMR minor	2
Non specific (out of 2)	0
Others (out of 95)1	0
Family history of sudden death	23
Clinically proven ARVC	1
Minor and non specific criteria for ARVC (not clinically proven)	3
Normal	15
LV hypertrophy	1
LV dyssynchrony	1
LV infarct	1
Dilated cardiomyopathy	1

¹Clinical data was available for only 81 patients. RV: Right ventricle; ARVC: Arrhythmogenic right ventricular cardiomyopathy; LV: Left ventricular.

Table 5 Positive predictive value in different groups

Clinical history - No ofpatients	Major criteria present	Clinically proven ARVC	Positive predictive value	Minor criteria present	Clinically proven ARVC	Positive predictive value
Arrhythmia (30%)	2	1	50%	3	2	67%
Family history of SCD (20%)	1	1	100%	1	0	0%
Others (50%)	1	1	100%	9	0	0%

ARVC: Arrhythmogenic right ventricular cardiomyopathy; SCD: Sudden cardiac death.