Background: Desmosomal changes, electric uncoupling, and surviving myocardial bundles in fibrofatty tissue characterize arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Resultant activation delay is pivotal for reentry and thereby ventricular tachycardia (VT). Current task force criteria (TFC) for diagnosis have limited sensitivity. The aim of this study was to assess the diagnostic value of additional criteria on activation delay and VT to improve identification of affected individuals.
Methods and results: ECG criteria were studied, while off drugs, in 50 index patients with proven ARVD/C according to TFC (TFC > or = 4 points) and 33 patients with probable ARVD/C (TFC 3 points, or TFC3), being 21 index patients and 12 family members of proven ARVD/C patients. Newly proposed additional criteria are (1) prolonged terminal activation duration in V(1)-V(3), an indicator of activation delay, (2) VT with left bundle-branch block morphology and superior axis, and (3) multiple VT morphologies. All index patients were screened for mutations in ARVD/C-related genes encoding desmosomal proteins. Altogether, 23 of 33 (70%) TFC3 patients fulfilled ARVD/C diagnosis when newly proposed criteria were applied additionally to current TFC. VT with left bundle-branch block morphology and superior axis or multiple VT morphologies were recorded in 12 and 9 of 33 TFC3 patients, respectively, all being index patients. When applying prolonged terminal activation duration additionally to TFC on depolarization/conduction abnormalities, 14 (42%) TFC3 patients fulfilled ARVD/C diagnosis. Results were not significantly different between mutation carriers and noncarriers.
Conclusions: Adding the newly proposed criteria to current TFC for ARVD/C will improve identification of affected individuals importantly, independent of outcome of DNA analyses.