title: New clinical and electrocardiographic classification in patients with idiopathic ventricular fibrillation.
abstract: BACKGROUND
  The presence of early repolarization (ER) recently has been considered as a prognostic marker for sudden cardiac death in patients with idiopathic ventricular fibrillation (IVF), but there are certain numbers of IVF patients lacking ER. We aimed to clarify the clinical and electrocardiographic characteristics of the patients with IVF in the presence and absence of ER.
  
  
  RESULTS
  We studied 64 consecutive IVF patients from the Japan Idiopathic Ventricular Fibrillation Study (J-IVFS) registry, which subjected with at least one episode of documented VF in the absence of structural heart diseases and excluding Brugada syndrome. We assessed clinical and electrophysiological characteristics in the IVF patients with and without ER. ER was defined as J-point elevation of >0.1 mV in either inferior or lateral leads. Twelve-lead electrocardiogram (ECG) demonstrated 24 (38%) of 64 patients with ER (ER[+] group) and the remaining 40 (62%) patients without ER (ER[-] group ). ER[+] group had a male predominance (92% for males) and ER[-] group revealed nearly equal distribution in both sexes. While no patients in ER[+] group showed intraventricular conduction disturbance (CD) with abnormal axis deviation and/or bundle branch block in ECG, 9 in ER[-] group had signs of CD (ER[-]/CD[+] subgroup). ER[-]/CD[+] subgroup had prolonged P-R interval and QRS duration compared to other patient groups.
  
  
  CONCLUSIONS
  We found 3 distinct ECG patterns in IVF patients. In addition to the presence and absence of ER, there is a subgroup without ER demonstrating intraventricular CD, which represents a distinct clinical entity of IVF.
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan. yseki@md.tsukuba.ac.jp
authors.forename: Yukio
authors.initials: Y
authors.lastname: Sekiguchi
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
authors.forename: Masahiko
authors.initials: M
authors.lastname: Takagi
authors.forename: Naohiko
authors.initials: N
authors.lastname: Aihara
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yokoyama
authors.forename: Masayasu
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D000704:Analysis of Variance; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012042:Registries; D014693:Ventricular Fibrillation / Q000145:classification* / Q000453:epidemiology / Q000503:physiopathology*
keywords: J wave; cardiac arrest; conduction disturbance; early repolarization; idiopathic ventricular fibrillation