title: The relationship between left ventricular scar and ventricular repolarization in patients with coronary artery disease: insights from late gadolinium enhancement magnetic resonance imaging.
abstract: OBJECTIVE
  The markers of ventricular repolarization corrected QT interval (QTc), QT dispersion (QTD) and Tpeak-to-Tend interval (Tpeak-end) have shown an association with sudden cardiac death (SCD) in the general population. However, their mechanistic relationship with SCD is unclear. The study aim was to evaluate the relationship between QTc, QTD, and Tpeak-end, and the extent and distribution of left ventricular (LV) scar in patients with coronary artery disease at high SCD risk.
  
  
  RESULTS
  We included 64 consecutive implantable cardioverter defibrillator (ICD) recipients (66 ± 11 years, 80% male, median left ventricular ejection fraction 30%) who had undergone late gadolinium enhancement cardiac magnetic resonance (CMR) imaging prior to device implantation over 4 years. Scar was quantified using the CMR images and characterized in terms of percent LV scar and number of LV segments with subendocardial/transmural scar. Repolarization parameters were measured on an electrocardiogram performed prior to ICD implantation. After adjustment for potential confounders there was a strong association between the number of limited subendocardial (1-25% transmurality) scar segments and QTc (P = 0.003), QTD (P = 0.002), and Tpeak-end (P = 0.008). However, there was no association between the repolarization parameters and percent LV scar or the amount of transmural scar. During a mean follow-up of 19 ± 10 months 19 (30%) patients received appropriate ICD therapy, but none of the repolarization parameters were associated with its occurrence.
  
  
  CONCLUSIONS
  In this pilot study there was a strong association between limited subendocardial LV scar and prolonged QTc, QTD, and Tpeak-end. However, there was no association between any of these repolarization markers and the delivery of appropriate ICD therapy.
authors.affiliation: Wessex Cardiothoracic Unit, Southampton University Hospitals NHS Trust, Tremona Road, Southampton SO16 6YD, UK. paul.andrew.scott@btinternet.com
authors.forename: Paul A
authors.initials: PA
authors.lastname: Scott
authors.forename: James A
authors.initials: JA
authors.lastname: Rosengarten
authors.forename: Anwar
authors.initials: A
authors.lastname: Shahed
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Yue
authors.forename: David C
authors.initials: DC
authors.lastname: Murday
authors.forename: Paul R
authors.initials: PR
authors.lastname: Roberts
authors.forename: Charles R
authors.initials: CR
authors.lastname: Peebles
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Harden
authors.forename: Nick P
authors.initials: NP
authors.lastname: Curzen
authors.forename: John M
authors.initials: JM
authors.lastname: Morgan
mesh_terms: D000368:Aged; D002921:Cicatrix / Q000150:complications / Q000473:pathology*; D003287:Contrast Media; D003324:Coronary Artery Disease / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D017147:Defibrillators, Implantable; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives; D009942:Organometallic Compounds; D010865:Pilot Projects; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000175:diagnosis* / Q000473:pathology*; D014693:Ventricular Fibrillation / Q000150:complications / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control*
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine
keywords: Arrhythmia; Coronary artery disease; Electrocardiogram; Implantable cardioverter defibrillator; Magnetic resonance imaging; Sudden death