The study was supported by Novartis.

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Background-Endocardial voltage mapping (EVM) identifies low-voltage right ventricular (RV) areas, which may representthe electroanatomic scar substrate of life-threatening tachyarrhythmias. We prospectively assessed the prognostic value of EVM in a consecutive series of patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). Methods and Results-We studied 69 consecutive ARVC/D patients (47 males; median age 35 years [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]) who underwent electrophysiological study and both bipolar and unipolar EVM. The extent of confluent bipolar (<1.5 mV) and unipolar (<6.0 mV) low-voltage electrograms was estimated using the CARTO-incorporated area calculation software. Fifty-three patients (77%) showed ≥1 RV electroanatomic scars with an estimated burden of bipolar versus unipolar lowvoltage areas of 24.8% (7.2-31.5) and 64. 8% (39.8-95.3), respectively (P=0.009). In the remaining patients with normal bipolar EVM (n=16; 23%), the use of unipolar EVM unmasked ≥1 region of low-voltage electrogram affecting 26.2% (11.6-38.2) of RV wall. During a median follow-up of 41 (28-56) months, 19 (27.5%) patients experienced arrhythmic events, such as sudden death (n=1), appropriate implantable cardioverter defibrillator interventions (n=7), or sustained ventricular tachycardia (n=11). Univariate predictors of arrhythmic outcome included previous cardiac arrest or syncope (hazard ratio=3.4; 95% confidence interval, 1.4-8.8; P=0.03) and extent of bipolar low-voltage areas (hazard ratio=1.7 per 5%; 95% confidence interval, 1.5-2; P<0.001), whereas the only independent predictor was the bipolar low-voltage electrogram burden (hazard ratio=1.6 per 5%; 95% confidence interval, 1.2-1.9; P<0.001). Patients with normal bipolar EVM had an uneventful clinical course. by genetically-determined myocardial loss and fibrofatty replacement and may provide a substrate for life-threatening re-entrant ventricular tachyarrhythmias. 4,[11][12][13][14] The assessment of mechanical consequences of myocardial fibrofatty scar has been traditionally based on imaging techniques such as echocardiography and angiography. 15,16 Among the techniques now available for direct imaging of ventricular myocardial lesion, endocardial voltage mapping (EVM) is an emerging tool that has the ability to accurately identify and quantify RV regions with low-amplitude electric signals (ie, electroanatomic scar areas), which reflect myocardial replaced tissue. [17][18][19][20][21][22][23][24] Although the technique has been demonstrated to enhance the accuracy for diagnosing ARVC/D, its value for arrhythmic risk stratification remains to be established. Hence this study was designed to prospectively evaluate the prognostic value of RV EVM in a cohort of ARVC/D patients during a long-term follow-up. Conclusions-The Methods Study PopulationThe study population included 69 consecutive patients (47 males; median age 35 years [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45])...

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In patients with ARVC, the extent of negative T-waves across 12-lead ECG allows noninvasive estimation of the amount of RV-EAS and prediction of EAS-related arrhythmic risk.