title: Diagnostic and prognostic values of the V-index, a novel ECG marker quantifying spatial heterogeneity of ventricular repolarization, in patients with symptoms suggestive of non-ST-elevation myocardial infarction.
abstract: BACKGROUND
  The V-index is an ECG marker quantifying spatial heterogeneity of ventricular repolarization. We prospectively assessed the diagnostic and prognostic values of the V-index in patients with suspected non-ST-elevation myocardial infarction (NSTEMI).
  
  
  METHODS
  We prospectively enrolled 497 patients presenting with suspected NSTEMI to the emergency department (ED). Digital 12-lead ECGs of five-minute duration were recorded at presentation. The V-index was automatically calculated in a blinded fashion. Patients with a QRS duration >120ms were ruled out from analysis. The final diagnosis was adjudicated by two independent cardiologists. The prognostic endpoint was all-cause mortality during 24months of follow-up.
  
  
  RESULTS
  NSTEMI was the final diagnosis in 14% of patients. V-index levels were higher in patients with AMI compared to other causes of chest pain (median 23ms vs. 18ms, p<0.001). The use of the V-index in addition to conventional ECG-criteria improved the diagnostic accuracy for the diagnosis of NSTEMI as quantified by area under the ROC curve from 0.66 to 0.73 (p=0.001) and the sensitivity of the ECG for AMI from 41% to 86% (p<0.001). Cumulative 24-month mortality rates were 99.4%, 98.4% and 88.3% according to tertiles of the V-index (p<0.001). After adjustment for age and important ECG and clinical parameters, the V-index remained an independent predictor of death.
  
  
  CONCLUSIONS
  The V-index, an ECG marker quantifying spatial heterogeneity of ventricular repolarization, significantly improves the accuracy and sensitivity of the ECG for the diagnosis of NSTEMI and independently predicts mortality during follow-up.
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; Lucerne University of Applied Sciences and Arts (HSLU), Horw, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Roger
authors.initials: R
authors.lastname: Abächerli
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Raphael
authors.initials: R
authors.lastname: Twerenbold
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Jasper
authors.initials: J
authors.lastname: Boeddinghaus
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nestelberger
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Mächler
authors.affiliation: Dipartimento di Informatica, Università degli Studi di Milano, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Sassi
authors.affiliation: Dipartimento di Informatica, Università degli Studi di Milano, Italy.
authors.forename: Massimo W
authors.initials: MW
authors.lastname: Rivolta
authors.affiliation: Dipartimento di Informatica, Università degli Studi di Milano, Italy.
authors.forename: Ebadollah Kheirati
authors.initials: EK
authors.lastname: Roonizi
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Italy.
authors.forename: Luca T
authors.initials: LT
authors.lastname: Mainardi
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Nikola
authors.initials: N
authors.lastname: Kozhuharov
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Maria
authors.initials: M
authors.lastname: Rubini Giménez
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Karin
authors.initials: K
authors.lastname: Wildi
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Karin
authors.initials: K
authors.lastname: Grimm
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Zaid
authors.initials: Z
authors.lastname: Sabti
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Petra
authors.initials: P
authors.lastname: Hillinger
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Puelacher
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Ivo
authors.initials: I
authors.lastname: Strebel
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Janosch
authors.initials: J
authors.lastname: Cupa
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Badertscher
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Roux
authors.affiliation: Signal Processing, Schiller AG, Baar, Switzerland.
authors.forename: Ramun
authors.initials: R
authors.lastname: Schmid
authors.affiliation: Signal Processing, Schiller AG, Baar, Switzerland.
authors.forename: Remo
authors.initials: R
authors.lastname: Leber
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Osswald
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Mueller
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; University of Basel, Basel, Switzerland. Electronic address: tobias.reichlin@usb.ch.
authors.forename: Tobias
authors.initials: T
authors.lastname: Reichlin
mesh_terms: D000368:Aged; D004562:Electrocardiography / Q000379:methods*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000072658:Non-ST Elevated Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D062206:Spatial Analysis