title: Clinical application of the fibrillation number in patients with an implantable cardioverter defibrillator.
abstract: BACKGROUND
  Although ventricular tachycardia/fibrillation (VT/VF) develops suddenly with catastrophic results, its prediction is limited. We tested the fibrillation number (FibN) for potential predictor of VT/VF using clinical data of implantable cardioverter-defibrillator (ICD) patients after validating the number by computational modeling.
  
  
  METHODS
  For clinical application of FibN, we used electrocardiography and echocardiography data: QRS width, QTc, and left ventricular (LV) end-systolic dimension (FibNVT/VF1) or LV end-diastolic dimension (FibNVT/VF2). We compared the maintenance duration of VT/VF for various FibN values using computational modeling, and tested FibNVT/VF in 142 patients with ICD for secondary prevention and 426 patients in age-sex matched control group (81.9% male, 56.1 ± 12.3 years old).
  
  
  RESULTS
  1. Computational results showed a positive correlation between VT/VF maintenance duration and FibN (R = 0.82, p < 0.001). 2. FibNVT/VFs were significantly higher in patients with ICD than in control (both FibNVT/VF1 and FibNVT/VF2, p < 0.001). 3. Within ICD group, FibNVT/VF values were higher in patients with cardiomyopathy than those without (both FibNVT/VF1 and FibNVT/VF2, p < 0.001). 4. During 50 ± 39 months follow-up period, the frequency of appropriate ICD therapy was higher in the high FibNVT/VF group (FibNVT/VF1, p = 0.001; FibNVT/VF2, p = 0.002). Both FibNVT/VF1 (HR 2.51, 95%CI 1.48-4.24, p = 0.001) and FibNVT/VF2 (HR 2.11, 95%CI 1.25-3.55, p = 0.005) were independently associated with appropriate ICD therapy in multi-variate analyses.
  
  
  CONCLUSIONS
  FibNVT/VF, a parameter based on wavelength and heart size, correlates well with maintenance of VT/VF in computational modeling, and may have predictive value for VT/VF events in patients with ICD for secondary prevention.
authors.affiliation: Division of Cardiology, Yonsei University Health System, Seoul, Republic of Korea.
authors.forename: Minki
authors.initials: M
authors.lastname: Hwang
authors.affiliation: Division of Cardiology, Yonsei University Health System, Seoul, Republic of Korea.
authors.forename: Hancheol
authors.initials: H
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Yonsei University Health System, Seoul, Republic of Korea.
authors.forename: Young-Seon
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Yonsei University Health System, Seoul, Republic of Korea.
authors.forename: Soonwon
authors.initials: S
authors.lastname: Chung
authors.affiliation: CU Medical Systems Incorporation, Wonju, Gangwon-Do, Republic of Korea.
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Mechanical and Biomedical Engineering, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea. Electronic address: ebshim@kangwon.ac.kr.
authors.forename: Eun Bo
authors.initials: EB
authors.lastname: Shim
authors.affiliation: Division of Cardiology, Yonsei University Health System, Seoul, Republic of Korea. Electronic address: hnpak@yuhs.ac.
authors.forename: Hui-Nam
authors.initials: HN
authors.lastname: Pak
mesh_terms: D003198:Computer Simulation; D017147:Defibrillators, Implantable; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D066230:Patient-Specific Modeling; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013813:Therapy, Computer-Assisted / Q000379:methods; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000503:physiopathology* / Q000517:prevention & control*
keywords: Arrhythmogenecity; Computational modeling; Implantable cardioverter defibrillator; Ventricular fibrillation; Ventricular tachycardia