Abstract 18375: Prognostic Value of Unipolar vs Bipolar Electroanatomic Voltage Mapping in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy/dysplasia
Background: electroanatomic voltage mapping (EVM) allows to identify and quantify low-voltage right ventricular (RV) areas, which may represent the electroanatomic scar substrate of life-threatening RV tachyarrhythmias. We prospectively assessed the prognostic value of EVM in a consecutive series of patients witharrhythmogenic right ventricular cardiomyopathy (ARVC).
Methods: the study population included 69 consecutive patients (47 male; age 37±14 years) fulfilling the International Task Force diagnostic criteria. All patients underwent electrophysiological study and high density EVM (195±22 points), using both bipolar and unipolar map techniques. The extent area of confluent bipolar (<1.5 mV) and unipolar (<6.0 mV) low-voltage electrograms was calculated with the CARTO software.
Results: Fifty-three patients (77%) showed ≥1 RV electroanatomic scar regions with an estimated burden of bipolar vs unipolar low-voltage areas of 25.5±12.7% and 66.5±18.4%, respectively (P<0.009). In all the remaining patients with normal bipolar-EVM (n=16; 23%) the use of unipolar EVM technique unmasked ≥1 region of low-voltage electrogram abnormality affecting 27.3±13.8% of RV wall. During 49±13 months of follow-up, 19 (27.5%) patients experienced major arrhythmic events, such as sudden death (n=1), appropriate ICD interventions (n=7) or sustained ventricular tachycardia (n=11). Univariate predictors of arrhythmic outcome included syncope (HR=2.4;95%CI:1.1-6.7;P=0.03), previous cardiac arrest (HR=3.7;95%CI:1.4-8.9;P=0.02), right precordial T-wave inversion (HR=9.3;95%CI:1.7-29) and extent of bipolar low-voltage areas (HR=1.7/5%;95%CI=1.5-2; P<0.001), while the only independent predictor was the bipolar low-voltage electrogram burden (HR=1.5/5%;95% CI:1.4-1.6;P<0.001). All patients with normal bipolar EVM had an uneventful clinical course despite the presence of unipolar scar areas.
Conclusions: The extent of bipolar RV endocardial low-voltage area is a powerful predictor of malignant arrhythmic events in ARVC/D, independently of medical history and RV datation/dysfunction. Non-transmural RV electroanatomic scar involvement (abnormal unipolar/normal bipolar EVM) characterized a low-risk subgroup of patients.
- © 2012 by American Heart Association, Inc.