Analysis of Site-specific Late Potentials Using a Novel Holter Signal-averaged Electrocardiography in Patients with Brugada Syndrome

Background The utility of late potentials on signal-averaged electrocardiography (SAECG) for risk stratification in patients with Brugada syndrome (BrS) remains controversial. Late potentials on conventional SAECG with Frank leads may be insufficiently sensitive to detect site-specific late potentials in right precordial leads. Objective The purpose of this study was to evaluate the utility of site-specific late potentials using a novel unipolar Holter-SAECG system for risk stratification in patients with BrS. Methods Consecutive symptomatic (n = 20) and asymptomatic (n = 21) patients with BrS who underwent investigation using conventional SAECG and a novel unipolar Holter-SAECG system were enrolled. We evaluated clinical characteristics and outcomes and compared late potentials on the 2 SAECGs between both groups and patients with and without cardiac events (CEs) (sudden cardiac death or sustained ventricular tachyarrhythmias) during the follow-up period. Results During mean follow-up of 76 months, 10 patients (24%) had CEs. There were no significant differences in late potentials on conventional SAECG between symptomatic and asymptomatic patients. On the Holter-SAECG system, RMS40 in lead V 2 in the third intercostal space (3L-V 2 ) at the nighttime was significantly lower in the symptomatic group than in the asymptomatic group (5.5 ± 0.8 μV and 8.2 ± 0.8 μV, respectively; P = .027). Univariate analysis of predictive values for CE showed that hazard ratios of daytime and nighttime RMS40 in lead 3L-V 2 of <7.7 μV and <6.1 μV were 7.58 and 6.14, respectively. Conclusion Site-specific late potentials in lead 3L-V 2 measured using the novel Holter-SAECG system may be a useful marker for high-risk patients with BrS.