PO-05-135 SIGNAL-AVERAGED ECG IN THE NORDIC ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY REGISTRY: ASSOCIATION WITH PREVALENT LIFE-THREATENING ARRHYTHMIAS AND ASCERTAINMENT OF CLINICAL DIAGNOSIS.

Abstract

In arrhythmogenic right ventricular cardiomyopathy (ARVC), minor depolarization criteria by TFC2010 include ventricular late potentials (LP) assessed using signal-averaged ECG (SAECG) and terminal activation duration (TAD). TAD is measured from a standard V1 lead, which favors its use in clinical practice, however its ability to fully replace LP in ARVC workup is not clear. 1. To assess the association between TAD and LP and the prevalence of life-threatening ventricular arrhythmias in patients with ARVC. 2. To assess diagnostic impact of SAECG by characterizing the subgroup of patients, who would not have received definite ARVC diagnosis if LP were not considered. Patients with definite ARVC or genotype-positive family members who underwent SAECG were included (n=358, 47% women, age 41±16 years, 43% probands, 67% definite ARVC). LP and TAD were defined according to TFC2010 criteria. TFC score was calculated by assigning 2 points for major and 1 for minor criterium. Ventricular tachycardia (VT) was defined as sustained VT, aborted cardiac arrest or appropriate ICD shock. Logistic regression adjusted for clinical covariates was used to test association of TAD and LP with prevalent VT. In a subgroup of patients with TFC score 4, i.e. minimally required for diagnosis, patients who would be reclassified into borderline category if LP not considered (LP-dependent, n=38) were compared with those who had TFC score 4 regardless of LP (LP-independent, n=30) in terms of proband status, prevalence of imaging criteria and VT. LP were found in 209 patients (58%); TAD in 65 (18%); 90 patients had prevalent VT (25%). LP was associated with prevalent VT (OR=2.5 95%CI 1.2-5.3; Sensitivity 84%, Specificity 50%) while TAD was not (OR=1.6 95%CI 0.7-3.6; Sensitivity 32%, Specificity 87%). In the LP-dependent group, 9 of 14 (64 %) probands had prevalent VT, 7 (50%) survived cardiac arrest and 4 (29%) were genotype-positive. Clinical characteristics did not demonstrate significant differences between LP-dependent and LP-independent subgroups. LP is independently associated with VT and is more sensitive than TAD in identification of patients with prevalent VT. LP were critical for ascertainment of ARVC diagnosis required for initiation of family screening in 9% probands. Although the diagnostic impact of LP varies depending on SAECG availability, our data support its use as a sensitive non-invasive diagnostic tool.