title: Fragmented QRS as a candidate marker for high-risk assessment in hypertrophic cardiomyopathy.
abstract: BACKGROUND
  The relationship between a fragmented QRS complex (fQRS) on 12-lead ECG and fatal arrhythmic events in hypertrophic cardiomyopathy (HCM) remains unclear.
  
  
  OBJECTIVE
  The purpose of this study was to investigate whether fQRS is associated with ventricular arrhythmic events (VAEs) in HCM patients.
  
  
  METHODS
  Of an initial cohort of 273 patients (57% male, mean age 55 years) diagnosed with HCM, 167 patients were included and divided into 2 groups: those with fQRS (n = 67) and those without fQRS (n = 100). fQRS was defined as notching of the R or S wave in 2 contiguous leads. VAEs were defined as nonsustained or sustained ventricular tachycardia (VT) or sudden cardiac death (SCD). Major arrhythmic events (MAEs) were sustained VT or SCD.
  
  
  RESULTS
  During mean follow-up of 6.3 years, univariate analysis showed that fQRS was significantly associated with increased VAEs (unadjusted hazard ratio [HR] 6.17, 95% confidence interval [CI] 2.46-15.49, P < .001) and MAEs (unadjusted HR 5.12, 95% CI 1.38-19.01, P = .014). Multivariate analysis revealed that fQRS was a strong independent predictor of VAEs (adjusted HR 6.28, 95% CI 2.49-15.84, P < .001) and MAEs (adjusted HR 6.04, 95% CI 1.49-24.39, P = .011). fQRS in the inferior leads was most closely related to MAEs compared to fQRS in other myocardial territories, and its inclusion in a risk calculator for mortality in HCM patients increased the positive predictive value from 8% to 25% in low-risk patients.
  
  
  CONCLUSIONS
  Presence of an fQRS may be a good candidate marker for prediction of VAE in patients with HCM.
authors.affiliation: Division of Cardiology, Eulji University Hospital, Daejeon, Eulji University College of Medicine, South Korea.
authors.forename: Ki-Woon
authors.initials: KW
authors.lastname: Kang
authors.affiliation: CardioNXT, Inc., Westminster, Colorado.
authors.forename: Ajit H
authors.initials: AH
authors.lastname: Janardhan
authors.affiliation: Division of Cardiology, Eulji University Hospital, Daejeon, Eulji University College of Medicine, South Korea.
authors.forename: Kyung Tae
authors.initials: KT
authors.lastname: Jung
authors.affiliation: Division of Biostatistics, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Moon-Hyoung
authors.initials: MH
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, South Korea. Electronic address: hyejin@yuhs.ac.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Hwang
mesh_terms: D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000503:physiopathology*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000209:etiology*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends
keywords: Fragmented QRS; Hypertrophic cardiomyopathy; Major arrhythmic events; Sudden cardiac death; Ventricular arrhythmic events