title: Left ventricular dyssynergy and dispersion as determinant factors of fatal ventricular arrhythmias in patients with mildly reduced ejection fraction.
abstract: OBJECTIVE
  Current guidelines recommend implantation of prophylactic implantable cardioverter-defibrillators (ICD) in patients with left ventricular (LV) ejection fraction (EF) <35%. We explored the prognostic factors of fatal ventricular arrhythmias for heart failure (HF) patients with LVEF ≥35%.
  
  
  RESULTS
  We retrospectively studied 72 patients with LVEF of 52 ± 12% (all ≥35%) who had undergone ICD implantation. Heterogeneity of LV regional myocardial contraction was defined as standard deviation of peak strain (dyssynergy index) and time-to-peak strain (dispersion index) from 18 LV segments determined by speckle tracking. Fatal ventricular arrhythmias with appropriate ICD therapy occurred in 34 patients (47%) during a median follow-up of 17 months. Receiver operating characteristic curve analysis identified dispersion index ≥101 ms and dyssynergy index ≥6.1% as predictors of fatal ventricular arrhythmias (P = 0.004 and P = 0.0001, respectively). In addition, the combination of dispersion index ≥101 ms and dyssynergy index ≥6.1% was the most predictive of fatal ventricular arrhythmias with a sensitivity of 77%, specificity of 79%, and area under the curve of 0.795 (P < 0.0001). A sequential Cox model based on clinical and conventional echocardiographic variables including age, gender, HF aetiology, and LVEF (χ(2) = 4.8) was improved, but not statistically significant (χ(2) = 4.9; P = 0.82), by addition of global longitudinal strain, whereas improvement by the addition of the dispersion index (χ(2) = 8.9; P = 0.04) and further improvement by the addition of the dyssynergy index (χ(2) = 20.2; P < 0.005).
  
  
  CONCLUSIONS
  Combined assessment of LV dyssynergy and dispersion can enhance predictive capability for fatal ventricular arrhythmias in patients with LVEF ≥35% and may have potential for better management of such patients.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Matsuzoe
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan tanakah@med.kobe-u.ac.jp.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Matsumoto
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Toki
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shimoura
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Ooka
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sano
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Sawa
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Motoji
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Mochizuki
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Ryo
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Fukuzawa
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoshida
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Hirata
mesh_terms: D001145:Arrhythmias, Cardiac / Q000401:mortality* / Q000503:physiopathology*; D017147:Defibrillators, Implantable; D004452:Echocardiography; D023381:Endpoint Determination; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000401:mortality* / Q000503:physiopathology*
keywords: dispersion; dyssynergy; echocardiography; implantable cardioverter-defibrillator; mild reduced left ventricular ejection fraction; ventricular arrhythmia