title: Fragmented QRS as a predictor of arrhythmic events in patients with hypertrophic obstructive cardiomyopathy.
abstract: OBJECTIVE
  This study aims to determine whether fragmented QRS (fQRS) in the surface electrocardiogram (ECG) at implantable cardioverter defibrillator (ICD) implant can predict arrhythmic events using appropriate therapy delivered by the ICD as a surrogate.
  
  
  BACKGROUND
  Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder associated with life-threatening arrhythmias frequently requiring an ICD. Seeking a noninvasive method of risk stratification remains a challenge.
  
  
  METHODS
  This paper is a retrospective, multicenter study of patients with HOCM and ICD. Surface 12-lead ECGs were analyzed. Appropriate therapy was validated by a blinded Core Lab. Univariate and multivariate analyses were performed. A p value of <0.05 was considered significant.
  
  
  RESULTS
  We included 102 patients from 13 centers. Mean age at implant was 41.16 ± 18.25 years, 52% were male. Mean left ventricular ejection fraction was 61.56 ± 9.46% and two thirds had heart failure according to the New York Heart Association class I. Secondary prophylaxis ICD implantation was the indication for implant in 40.2% of cases. About half received a single-chamber ICD. fQRS was present at the time of diagnosis in 21 and in 54% at ICD implant. At a mean follow-up of 47.8 ± 39.3 months, 41 patients (40.2%) presented with appropriate therapy. In a multivariate logistic regression, predictors of appropriate therapy included fQRS at implant (odds ratio [OR], 16.4; 95% confidence interval [CI], 3.6-74.0; p = 0.0003), history of combined ventricular tachycardia/fibrillation/sudden death (OR, 14.3; 95% CI, 3.2-69.3; p = 0.001) and history of syncope (OR, 5.5; 95% CI, 1.5-20.4; p = 0.009). Ten deaths (9.8%) occurred during the follow-up. fQRS in the lateral location increased the risk of appropriate therapy (p < 0.0001).
  
  
  CONCLUSIONS
  fQRS predicts arrhythmic events in patients with HOCM and should be considered in a model of risk stratification.
authors.affiliation: Arrhythmia Unit, Department of Cardiology, Hospital Español de Mendoza, Mendoza, Argentina, femeniafavier@hotmail.com.
authors.forename: Francisco
authors.initials: F
authors.lastname: Femenía
authors.forename: Maurico
authors.initials: M
authors.lastname: Arce
authors.forename: Jorge
authors.initials: J
authors.lastname: Van Grieken
authors.forename: Emilce
authors.initials: E
authors.lastname: Trucco
authors.forename: Luis
authors.initials: L
authors.lastname: Mont
authors.forename: Mauricio
authors.initials: M
authors.lastname: Abello
authors.forename: José L
authors.initials: JL
authors.lastname: Merino
authors.forename: Máximo
authors.initials: M
authors.lastname: Rivero-Ayerza
authors.forename: Bulent
authors.initials: B
authors.lastname: Gorenek
authors.forename: Carlos
authors.initials: C
authors.lastname: Rodriguez
authors.forename: Wilma M
authors.initials: WM
authors.lastname: Hopman
authors.forename: Adrian
authors.initials: A
authors.lastname: Baranchuk
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control*; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control*; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D017147:Defibrillators, Implantable; D004562:Electrocardiography / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D038622:Internationality; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D055815:Young Adult