Abstract 1830: New ECG Criteria for Diagnosis of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

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Introduction Desmosomal changes, electrical uncoupling and surviving myocardial bundles embedded in fibrofatty tissue are hallmarks of activation delay (AD) in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). AD is pivotal for reentrant mechanisms and thereby ventricular tachycardia (VT). At present, generally accepted Task Force Criteria (TFC) are used for clinical diagnosis of ARVD/C. We propose additional criteria (AC) on AD and VT to improve identification of affected individuals. Methods AD and VT-related electrocardiographic criteria were studied, while off drugs, in 42 patients with proven ARVD/C according to TFC, and 23 controls with idiopathic VT from the RV outflow tract. TFC assessed: epsilon waves, QRS width >110ms in V1–3 in absence of RBBB and negative T-waves in V2 and beyond. The 3 new AC are: prolonged S-wave upstroke in V1–3 (≥55ms from nadir of S to end of depolarization) occurrence of LBBB like VT with axis −30° to −150°and number of different monomorphic VT morphologies (different when Δ axis ≥30°; spontaneous and induced by programmed electrical stimulation (PES)). All ARVD/C patients were screened for mutations in genes encoding desmosomal proteins. Results For comparison of ARVD/C patients (pts) and controls: see table . In ARVD/C pts mean S-wave upstroke duration was 63±20 ms (range 40–140), mean number of different spontaneous VTs 1.8±0.95 (range 0–5) and mean number of spontaneous+induced VTs 2.8±1.08 (range 1–5). All VTs showed LBBB morphology. Plakophilin-2 mutations were identified in 25 (60%) of ARVD/C pts. Parameters measured were not significantly different between mutation carriers and non-carriers. Conclusions The newly proposed criteria are sensitive and specific for ARVD/C and thereby useful for its diagnosis, independent of outcome of DNA analysis. Prolonged S-wave upstroke is the most sensitive ECG indicator of activation delay during sinus rhythm. PES contributes to yield of VT morphologies.