title: Fragmented QRS Is a Novel Risk Factor for Ventricular Arrhythmic Events After Receiving Cardiac Resynchronization Therapy in Nonischemic Cardiomyopathy.
abstract: BACKGROUND
  A fragmented QRS (fQRS) is reported to be associated with a poor prognosis or sudden cardiac death (SCD) in patients with Brugada syndrome or ischemic heart disease. However, no studies have clarified the impact of the presence of an fQRS on SCD or ventricular arrhythmic events in patients receiving cardiac resynchronization therapy (CRT). This study aimed to clarify this point in patients with nonischemic cardiomyopathy.
  
  
  RESULTS
  This study included 137 heart failure patients with nonischemic cardiomyopathy who received CRT (NYHA functional class: II/III/IV = 25/84/28). The 12-lead ECGs before and after CRT were analyzed. The presence of an fQRS was decided in accordance with the definition in previous papers. Before the CRT, an fQRS was observed in 67 patients (fQRS-pre; 49%). However, it was masked in 35 (52% of fQRS-pre) patients after the CRT. Inversely, in 70 patients in whom an fQRS was absent before the CRT, it appeared after the CRT in 15 (21%) patients. As a result, 47 patients (34%) had an fQRS after the CRT (fQRS-post), and it was less than that before the CRT (P = 0.014). During 18 months of follow-up, SCD or ventricular arrhythmic events were observed more frequently in patients with an fQRS-post than in those without (36.2% vs. 3.3%, P < 0.001). A Cox regression analysis revealed that an fQRS-post was significantly associated with those events (hazard ratio = 9.18; 95% confidence interval = 2.45-34.48, P = 0.001).
  
  
  CONCLUSIONS
  In patients with nonischemic cardiomyopathy who received CRT, an fQRS-post was independently associated with SCD or ventricular arrhythmic events.
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Miyako
authors.initials: M
authors.lastname: Igarashi
authors.affiliation: Department of Cardiovascular Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tada
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Hiro
authors.initials: H
authors.lastname: Yamasaki
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kuroki
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishizu
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Seo
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Machino
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Murakoshi
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Sekiguchi
authors.affiliation: Cardiovascular Division, Tsukuba Medical Center Hospital, Tsukuba, Ibaraki, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Noguchi
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nogami
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects* / Q000401:mortality; D009202:Cardiomyopathies / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D016009:Chi-Square Distribution; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: cardiac resynchronization therapy; fragmented QRS; heart failure; implantable cardioverter defibrillator; sudden cardiac death; ventricular arrhythmia