Abstract
Cardiac sarcoidosis (CS) with right ventricular (RV) involvement can mimic arrhythmogenic right ventricular cardiomyopathy (ARVC). Histopathological differences may result in disease-specific RV activation patterns detectable on the 12-lead electrocardiogram. Dominant subepicardial scar in ARVC leads to delayed activation of areas with reduced voltages, translating into terminal activation delay and occasionally (epsilon) waves with a small amplitude. Conversely, patchy transmural RV scar in CS may lead to conduction block and therefore late activated areas with preserved voltages reflected as preserved R' waves. The purpose of this study was to evaluate the distinct terminal activation patterns in precordial leads V1 through V3 as a discriminator between CS and ARVC. Thirteen patients with CS affecting the RV and 23 patients with gene-positive ARVC referred for ventricular tachycardia ablation were retrospectively included in a multicenter approach. A non-ventricular-paced 12-lead surface electrocardiogram was analyzed for the presence and the surface area of the R' wave (any positive deflection from baseline after an S wave) in leads V1 through V3. An R' wave in leads V1 through V3 was present in all patients with CS compared to 11 (48%) patients with ARVC (P=.002). An algorithm including a PR interval of ≥220 ms, the presence of an R' wave, and the surface area of the maximum R' wave in leads V1 through V3 of ≥1.65 mm2 had 85% sensitivity and 96% specificity for diagnosing CS, validated in a second cohort (18 CS and 40 ARVC) with 83% sensitivity and 88% specificity. An easily applicable algorithm including PR prolongation and the surface area of the maximum R' wave in leads V1 through V3 of ≥1.65 mm2 distinguishes CS from ARVC. This QRS terminal activation in precordial leads V1 through V3 may reflect disease-specific scar patterns.
Highlights
Arrhythmogenic right ventricular cardiomyopathy (ARVC) and cardiac sarcoidosis (CS) are the most important underlying etiologies for scar-related ventricular tachycardias (VTs) from the right ventricle (RV).[1]
It has been suggested that the presence of a right bundle branch block (RBBB)-like pattern in ARVC is caused by intra-RV delay rather than proximal conduction block,[8] reflected as an atypical pattern with R0/S ratio, 1 on the ECG.[12]
Patients with ARVC and CS with RV involvement from 7 centers (Boston, Massachusetts; Hokkaido, Japan; Leiden, The Netherlands; Ann Arbor, Michigan; M€unster, Germany; Nashville, Tennessee; and Prague, The Czech Republic) who presented with a VT proven or presumably from the RV and a nonpaced ECG available were eligible for inclusion
Summary
Arrhythmogenic right ventricular cardiomyopathy (ARVC) and cardiac sarcoidosis (CS) are the most important underlying etiologies for scar-related ventricular tachycardias (VTs) from the right ventricle (RV).[1]. It has been suggested that the presence of a RBBB-like pattern in ARVC is caused by intra-RV delay rather than proximal conduction block,[8] reflected as an atypical pattern with R0/S ratio , 1 on the ECG.[12]. Patchy transmural RV scar in CS may lead to conduction block and late activated areas with preserved voltages reflected as preserved R0 waves
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