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

Abstract

【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 may be insufficiently sensitive to detect the site-specific late potentials of the right ventricular outflow tract in right precordial leads. 【Objective】This study aimed 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 both two SAECGs between both groups and patients with and without sudden cardiac death or sustained ventricular tachyarrhythmias during the follow-up period. 【Results】There were no significant differences in late potentials on conventional SAECG between symptomatic and asymptomatic patients. On the Holter-SAECG system, the value of RMS40 in lead V₂ in the third intercostal space（3L-V₂）at night was significantly lower in the symptomatic group than in the asymptomatic group（5.5±0.8 and 8.2±0.8μV, respectively ; p＝0.027）. Univariate analysis of predictive values for cardiac event CE showed that hazard ratios of daytime and nighttime RMS40 in lead 3L-V₂ of＜7.7μV and＜6.1μV were 7.58 and 6.14, respectively. 【Conclusions】Site-specific late potentials in lead 3L-V₂ detected using the novel Holter-SAECG may be a useful marker for high-risk patients with BrS.