title: Myocardial mechanical and QTc dispersion for the detection of significant coronary artery disease.
abstract: OBJECTIVE
  Ischaemic but viable myocardium may exhibit prolongation of contraction and QT interval duration, but it is largely unknown whether non-invasive assessment of regional heterogeneities of myocardial deformation and QT interval duration could identify patients with significant coronary artery disease (CAD).
  
  
  RESULTS
  We retrospectively studied 205 patients with suspected CAD who underwent coronary angiography. QTc dispersion was assessed from a 12-lead electrocardiogram (ECG) as the difference between the longest and shortest QTc intervals. Contraction duration was assessed as time from the ECG R-(Q-)wave to peak longitudinal strain in each of 18 left ventricular segments. Mechanical dispersion was defined as either the standard deviation of 18 time intervals (dispersionSD18) or as the difference between the longest and shortest time intervals (dispersiondelta). Longitudinal strain was measured by speckle tracking echocardiography. Mean contraction duration was longer in patients with significant CAD compared with control subjects (428 ± 51 vs. 410 ± 40 ms; P = 0.032), and it was correlated to QTc interval duration (r = 0.47; P < 0.001). In contrast to QTc interval duration and dispersion, both parameters of mechanical dispersion were independently associated with CAD (P < 0.001) and had incremental value over traditional risk factors, wall motion abnormalities, and global longitudinal strain (GLS) for the detection of significant CAD.
  
  
  CONCLUSIONS
  The QTc interval and myocardial contraction duration are related to the presence of significant CAD in patients without a history of previous myocardial infarction. Myocardial mechanical dispersion has an incremental value to GLS for identifying patients with significant CAD.
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia ivan.stankovic@gmx.com future.ivan@gmail.com.
authors.forename: Ivan
authors.initials: I
authors.lastname: Stankovic
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Biljana
authors.initials: B
authors.lastname: Putnikovic
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Janicijevic
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Milica
authors.initials: M
authors.lastname: Jankovic
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Radosava
authors.initials: R
authors.lastname: Cvjetan
authors.affiliation: Pacemaker Center, Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Sinisa
authors.initials: S
authors.lastname: Pavlovic
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Tijana
authors.initials: T
authors.lastname: Kalezic-Radmili
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Milos
authors.initials: M
authors.lastname: Panic
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Predrag
authors.initials: P
authors.lastname: Milicevic
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Ilic
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Vojkan
authors.initials: V
authors.lastname: Cvorovic
authors.affiliation: Department of Cardiology, Clinical Hospital Centre Zemun, Faculty of Medicine, University of Belgrade, Vukova 9, Belgrade 11070, Serbia.
authors.forename: Aleksandar N
authors.initials: AN
authors.lastname: Neskovic
mesh_terms: D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000401:mortality; D004452:Echocardiography / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction / Q000502:physiology*; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000401:mortality; D015588:Observer Variation; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D012737:Sex Factors; D018709:Statistics, Nonparametric; D015996:Survival Rate
keywords: QT dispersion; QT interval; coronary artery disease; mechanical dispersion