title: Ethnic differences in the association of QRS duration with ejection fraction and outcome in heart failure.
abstract: QRS duration (QRSd) criteria for device therapy in heart failure (HF) were derived from predominantly white populations and ethnic differences are poorly understood.
  
  
  
  We compared the association of QRSd with ejection fraction (EF) and outcomes between 839 Singaporean Asian and 11 221 Swedish white patients with HF having preserved EF (HFPEF)and HF having reduced EF (HFREF) were followed in prospective population-based HF studies.
  
  
  
  Compared with whites, Asian patients with HF were younger (62 vs 74 years, p<0.001), had smaller body size (height 163 vs 171 cm, weight 70 vs 80 kg, both p<0.001) and had more severely impaired EF (EF was <30% in 47% of Asians vs 28% of whites). Overall, unadjusted QRSd was shorter in Asians than whites (101 vs 104 ms, p<0.001). Lower EF was associated with longer QRSd (p<0.001), with a steeper association among Asians than whites (pinteraction<0.001), independent of age, sex and clinical covariates (including body size). Excluding patients with left bundle branch block (LBBB) and adjusting for clinical covariates, QRSd was similar in Asians and whites with HFPEF, but longer in Asians compared with whites with HFREF (p=0.001). Longer QRSd was associated with increased risk of HF hospitalisation or death (absolute 2-year event rate for ≤120 ms was 40% and for >120 ms it was 52%; HR for 10 ms increase of QRSd was 1.04 (1.03 to 1.06), p<0.001), with no interaction by ethnicity.
  
  
  
  We found ethnic differences in the association between EF and QRSd among patients with HF. QRS prolongation was similarly associated with increased risk, but the implications for ethnicity-specific QRSd cut-offs in clinical decision-making require further study.
authors.affiliation: ICIN-Netherlands Heart Institute, Utrecht, The Netherlands Laboratory of Experimental Cardiology, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Crystel M
authors.initials: CM
authors.lastname: Gijsberts
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lina
authors.initials: L
authors.lastname: Benson
authors.affiliation: Department of Cardiology, Linköping University, Linköping, Sweden Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Dahlström
authors.affiliation: National Heart Centre, Singhealth, Singapore, Singapore.
authors.forename: David
authors.initials: D
authors.lastname: Sim
authors.affiliation: Department of Cardiology, Tan Tock Seng Hospital, Singapore, Singapore.
authors.forename: Daniel P S
authors.initials: DP
authors.lastname: Yeo
authors.affiliation: Department of Cardiology, Khoo Teck Puat Hospital, Singapore, Singapore.
authors.forename: Hean Yee
authors.initials: HY
authors.lastname: Ong
authors.affiliation: Department of Medicine/Cardiology, Singapore General Hospital, Singapore, Singapore Duke-NUS, Singapore, Singapore.
authors.forename: Fazlur
authors.initials: F
authors.lastname: Jaufeerally
authors.affiliation: Department of Cardiology, Changi General Hospital, Singapore, Singapore.
authors.forename: Gerard K T
authors.initials: GK
authors.lastname: Leong
authors.affiliation: Yong Loo Lin School of Medicine, National University, Singapore, Singapore Cardiac Department, National University Health System, Singapore, Singapore.
authors.forename: Lieng H
authors.initials: LH
authors.lastname: Ling
authors.affiliation: Yong Loo Lin School of Medicine, National University, Singapore, Singapore Cardiac Department, National University Health System, Singapore, Singapore Cardiovascular Research Institute, National University, Singapore, Singapore Christchurch Heart Institute, University of Otago, Christchurch, New Zealand.
authors.forename: A Mark
authors.initials: AM
authors.lastname: Richards
authors.affiliation: ICIN-Netherlands Heart Institute, Utrecht, The Netherlands Laboratory of Experimental Cardiology, University Medical Centre Utrecht, Utrecht, The Netherlands Yong Loo Lin School of Medicine, National University, Singapore, Singapore Cardiovascular Research Institute, National University, Singapore, Singapore.
authors.forename: Dominique P V
authors.initials: DP
authors.lastname: de Kleijn
authors.affiliation: Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden Department of Cardiology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Lars H
authors.initials: LH
authors.lastname: Lund
authors.affiliation: National Heart Centre, Singhealth, Singapore, Singapore Duke-NUS, Singapore, Singapore Yong Loo Lin School of Medicine, National University, Singapore, Singapore Cardiovascular Research Institute, National University, Singapore, Singapore.
authors.forename: Carolyn S P
authors.initials: CS
authors.lastname: Lam
mesh_terms: D000200:Action Potentials; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D000066491:Clinical Decision-Making; D015897:Comorbidity; D005260:Female; D054624:Health Status Disparities; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000208:ethnology* / Q000503:physiopathology* / Q000628:therapy; D006339:Heart Rate; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012042:Registries; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D013318:Stroke Volume; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D044465:White People
keywords: ECG/electrocardiogram