Activation delay and VT parameters in arrhythmogenic right ventricular dysplasia/cardiomyopathy: Toward improvement of diagnostic ECG criteria

Activation Delay and VT Parameters. Introduction: Desmosomal changes, electrical uncoupling, and surviving myocardial bundles embedded in fibrofatty tissue are hallmarks of activation delay in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Currently, generally accepted task force criteria (TFC) are used for clinical diagnosis. We propose additional criteria based on activation delay and ventricular tachycardia (VT) to improve identification of affected individuals. Methods and Results: Activation delay and VT-related 12-lead electrocardiographic (ECG) criteria were studied, while off drugs, in 42 patients with proven ARVD/C according to TFC, and 27 controls with idiopathic VT from the RV outflow tract. Two of three measured TFC could only be identified in a small minority of ARVD/C patients. Additional ECG criteria proposed in this study included (a) prolonged terminal activation duration, an indicator of activation delay; (b) VT with LBBB morphology and superior axis; and (c) multiple different VT morphologies. These criteria were met in 30 (71%), 28 (67%), and 37 (88%) ARVD/C patients, respectively, and in one control patient (P < 0.001). Electrophysiologic studies contributed importantly to yield different VT morphologies. Pathogenic plakophilin-2 mutations were identified in 25 (60%) of ARVD/C patients and in none of the controls. In ARVD/C patients, parameters measured were not significantly different between mutation carriers and noncarriers, except for negative T waves in V1-3, occurring more frequently in patients with mutation. Conclusions: The proposed additional criteria are specific for ARVD/C and more sensitive than the current TFC. Therefore, adding the newly proposed criteria to current TFC could improve ARVD/C diagnosis, independent of DNA analysis.