title: Electro-mechanical characteristics of myocardial infarction border zones and ventricular arrhythmic risk: novel insights from grid-tagged cardiac magnetic resonance imaging.
abstract: OBJECTIVE
  To investigate whether grid-tag myocardial strain evaluation can characterise 'border-zone' peri-infarct region and identify patients at risk of ventricular arrhythmia as the peri-infarct myocardial zone may represent an important contributor to ventricular arrhythmia following ST-segment elevation myocardial infarction (STEMI).
  
  
  METHODS
  Forty-five patients with STEMI underwent cardiac magnetic resonance (CMR) imaging on days 3 and 90 following primary percutaneous coronary intervention (PCI). Circumferential peak circumferential systolic strain (CS) and strain rate (CSR) were calculated from grid-tagged images. Myocardial segments were classified into 'infarct', 'border-zone', 'adjacent' and 'remote' regions by late-gadolinium enhancement distribution. The relationship between CS and CSR and these distinct myocardial regions was assessed. Ambulatory Holter monitoring was performed 14 days post myocardial infarction (MI) to estimate ventricular arrhythmia risk via evaluation of heart-rate variability (HRV).
  
  
  RESULTS
  We analysed 1,222 myocardial segments. Remote and adjacent regions had near-normal parameters of CS and CSR. Border-zone regions had intermediate CS (-9.0 ± 4.6 vs -5.9 ± 7.4, P < 0.001) and CSR (-86.4 ± 33.3 vs -73.5 ± 51.4, P < 0.001) severity compared with infarct regions. Patients with 'border-zone' peri-infarct regions had reduced very-low-frequency power on HRV analysis, which is a surrogate for ventricular arrhythmia risk (P = 0.03).
  
  
  CONCLUSIONS
  Grid-tagged CMR-derived myocardial strain accurately characterises the mechanical characteristics of 'border-zone' peri-infarct region. Presence of 'border-zone' peri-infarct region correlated with a surrogate marker of heightened arrhythmia risk following STEMI.
  
  
  CONCLUSIONS
  • Grid-tagged cardiac magnetic resonance (CMR) offers new insights into myocardial mechanical function. • Grid-tagged CMR identified different characteristics in 'border-zone' and 'adjacent' peri-infarct myocardial regions. • Reduced very-low-frequency (VLF) power is associated with arrhythmic and mortality risk. • The presence of 'border-zone' peri-infarct region correlated with reduced VLF power.
authors: Cardiovascular Research Centre, Royal Adelaide Hospital and Discipline of Medicine, University of Adelaide, Adelaide, South Australia.
authors: Dennis T L
authors: DT
authors: Wong
authors: Michael J
authors: MJ
authors: Weightman
authors: Mathias
authors: M
authors: Baumert
authors: Hussam
authors: H
authors: Tayeb
authors: James D
authors: JD
authors: Richardson
authors: Rishi
authors: R
authors: Puri
authors: Angela G
authors: AG
authors: Bertaso
authors: Kurt C
authors: KC
authors: Roberts-Thomson
authors: Prashanthan
authors: P
authors: Sanders
authors: Matthew I
authors: MI
authors: Worthley
authors: Stephen G
authors: SG
authors: Worthley
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000473:pathology*; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D005682:Gadolinium / Q000494:pharmacology; D006339:Heart Rate; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000379:methods; D009203:Myocardial Infarction / Q000473:pathology*; D009206:Myocardium / Q000473:pathology*; D015588:Observer Variation; D015203:Reproducibility of Results; D012306:Risk; D018487:Ventricular Dysfunction, Left / Q000473:pathology
chemical_list: D003287:Contrast Media; D005682:Gadolinium