title: Identification of high-risk Brugada syndrome patients by combined analysis of late potential and T-wave amplitude variability on ambulatory electrocardiograms.
abstract: BACKGROUND
  Risk stratification is important in the management of Brugada syndrome (BrS). Late potentials (LPs) and T-wave amplitude variability (TAV) in high-resolution ambulatory electrocardiography (ECG) were retrospectively investigated.
  
  
  RESULTS
  One hundred and twenty-seven patients diagnosed with BrS on 12-lead ECG were classified into 3 groups: documented ventricular fibrillation (VF)/asystole (n=19), episodes of syncope alone (n=30), and asymptomatic (n=78). Healthy volunteers were enrolled as controls (n=25). In the BrS patients, LPs showed appreciable circadian periodicity; filtered QRS duration (fQRS) and duration of the terminal low-amplitude signal <40 μV (LAS40) increased, whereas root mean square voltage of the terminal 40 ms of the fQRS (RMS40) decreased at night compared with the day. TAV did not have such a circadian periodicity. LP-positive incidence (night-time) and peak TAV were as follows: VF/asystole>syncope/asymptomatic>control (P<0.001). VF/asystole was discriminated from control at a ratio of 81-84% by night-time LPs (fQRS >116 ms, LAS40 >35 ms, RMS40 <25 μV) or peak TAV (>54 μV); VF/asystole was discriminated from syncope/asymptomatic at a ratio of 60-69%, by night-time LPs (fQRS >122 ms, LAS40 >42 ms, RMS40 <18μV) or peak TAV (>58 μV). Combined analysis of LPs and peak TAV increased the discriminant ratio up to 93% and 77%, respectively.
  
  
  CONCLUSIONS
  Analysis of both LPs and TAV (taking circadian periodicity into account) is useful in identification of high-risk BrS patients.
authors: Department of Cardiovascular Medicine, Tokai University School of Medicine, Isehara, Japan. ko1@is.icc.u-tokai.ac.jp
authors: Koichiro
authors: K
authors: Yoshioka
authors: Mari
authors: M
authors: Amino
authors: Wojciech
authors: W
authors: Zareba
authors: Makiyoshi
authors: M
authors: Shima
authors: Atsushi
authors: A
authors: Matsuzaki
authors: Toshiharu
authors: T
authors: Fujii
authors: Shigetaka
authors: S
authors: Kanda
authors: Yoshiaki
authors: Y
authors: Deguchi
authors: Yoshinori
authors: Y
authors: Kobayashi
authors: Yuji
authors: Y
authors: Ikari
authors: Itsuo
authors: I
authors: Kodama
authors: Teruhisa
authors: T
authors: Tanabe
mesh_terms: D000328:Adult; D053840:Brugada Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000502:physiology; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006323:Heart Arrest / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010507:Periodicity; D012189:Retrospective Studies; D012307:Risk Factors; D013575:Syncope / Q000503:physiopathology; D014693:Ventricular Fibrillation / Q000503:physiopathology