title: Quantitative assessment of ST segment elevation in Brugada patients.
abstract: BACKGROUND
  ST segment elevation in the right precordial leads constitutes the electrocardiogram (ECG) hallmark of Brugada syndrome (BS). This pattern is variable and can be concealed, but the magnitude and the cause of ST segment fluctuations have been poorly investigated.
  
  
  OBJECTIVE
  Our goal was to quantify ST changes and to assess rate and autonomic influences on ST level.
  
  
  METHODS
  A 12-lead ECG was continuously recorded during 24 hours in 20 patients with BS (ages 49 +/- 12) and 10 healthy subjects (ages 32 +/- 7). Using two-dimensional binning we obtained average QRS-T complexes every 30 minutes (time bins) and at different RR intervals (rate bins) for each subject. ST level was measured at five different points located 90, 100, 110, 120, and 140 ms after Q onset (Qo). In BS patients, the highest ST elevation was measured 110 ms after Qo (Qo+110).
  
  
  RESULTS
  ST level changes between time points were significantly greater in patients with BS compared with control subjects: on lead V2, the range of ST level at Qo+110 was 264 +/- 85 microV in BS and 91 +/- 22 microV in control subjects (P <.01). In BS, ST level decreased with heart rate acceleration: the difference in ST level at Qo+110 for RR = 900 and 600 ms was 55 +/- 53 microV (P <.01). HFnu was positively, although weakly, correlated with ST level (R(2) = 0.02, P <.01).
  
  
  CONCLUSIONS
  ECG changes observed in patients with BS are related in part to heart rate influences on ST segment level. These spontaneous fluctuations over a 24-hour time period suggest that Holter recordings may improve the ECG diagnosis sensitivity in BS.
authors.affiliation: Lariboisière University Hospital, Paris, France. Fabrice.extramiana@lrb.ap-hop-paris.fr
authors.forename: Fabrice
authors.initials: F
authors.lastname: Extramiana
authors.forename: Julien
authors.initials: J
authors.lastname: Seitz
authors.forename: Pierre
authors.initials: P
authors.lastname: Maison-Blanche
authors.forename: Fabio
authors.initials: F
authors.lastname: Badilini
authors.forename: Abdeddayem
authors.initials: A
authors.lastname: Haggui
authors.forename: Seiji
authors.initials: S
authors.lastname: Takatsuki
authors.forename: Paul
authors.initials: P
authors.lastname: Milliez
authors.forename: Isabelle
authors.initials: I
authors.lastname: Denjoy
authors.forename: Bruno
authors.initials: B
authors.lastname: Cauchemez
authors.forename: Philippe
authors.initials: P
authors.lastname: Beaufils
authors.forename: Antoine
authors.initials: A
authors.lastname: Leenhardt
mesh_terms: D000328:Adult; D000368:Aged; D004562:Electrocardiography; D005500:Follow-Up Studies; D006323:Heart Arrest / Q000209:etiology / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D013577:Syndrome; D014693:Ventricular Fibrillation / Q000150:complications / Q000503:physiopathology*