title: Global myocardial strain assessment by different imaging modalities to predict outcomes after ST-elevation myocardial infarction: A systematic review.
abstract: OBJECTIVE
  To conduct a systematic review relating myocardial strain assessed by different imaging modalities for prognostication following ST-elevation myocardial infarction (STEMI).
  
  
  METHODS
  An online literature search was performed in PubMed and OVID(®) electronic databases to identify any studies that assessed global myocardial strain parameters using speckle-tracking echocardiography (STE) and/or cardiac magnetic resonance imaging (CMR) techniques [either myocardial tagging or feature tracking (FT) software] in an acute STEMI cohort (days 0-14 post-event) to predict prognosis [either development of major adverse cardiac events (MACE)] or adverse left ventricular (LV) remodelling at follow-up (≥ 6 mo for MACE, ≥ 3 mo for remodelling). Search was restricted to studies within the last 20 years. All studies that matched the pre-defined search criteria were reviewed and their results interpreted. Due to considerable heterogeneity between studies, meta-analysis was not performed.
  
  
  RESULTS
  A total of seven studies (n = 7) were identified that matched the search criteria. All studies used STE to evaluate strain parameters - five (n = 5) assessed global longitudinal strain (GLS) (n = 5), one assessed GLS rate (GLS-R) (n = 1) and one assessed both (n = 1). Three studies showed that GLS independently predicted the development of adverse LV remodelling by multivariate analysis - odds ratio between 1.19 (CI: 1.04-1.37, P < 0.05) and 10 (CI: 6.7-14, P < 0.001) depending on the study. Four studies showed that GLS predicted the development of MACE - hazard ratio (HR) between 1.1 (CI: 1-1.1, P = 0.006) and 2.34 (1.10-4.97, P < 0.05). One paper found that GLS-R could significantly predict MACE - HR 18 (10-35, P < 0.001) - whilst another showed it did not. GLS < -10.85% had sensitivity/specificity of 89.7%/91% respectively for predicting the development of remodelling whilst GLS < -13% could predict the development of MACE with sensitivity/specificity of 100%/89% respectively. No suitable studies were identified that assessed global strain by CMR tagging or FT techniques.
  
  
  CONCLUSIONS
  GLS measured acutely post-STEMI by STE is a predictor of poor prognosis. Further research is needed to show that this is true for CMR-based techniques.
authors.affiliation: Abhishek Shetye, Sheraz A Nazir, Iain B Squire, Gerald P McCann, Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester LE3 9QP, United Kingdom.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Shetye
authors.affiliation: Abhishek Shetye, Sheraz A Nazir, Iain B Squire, Gerald P McCann, Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester LE3 9QP, United Kingdom.
authors.forename: Sheraz A
authors.initials: SA
authors.lastname: Nazir
authors.affiliation: Abhishek Shetye, Sheraz A Nazir, Iain B Squire, Gerald P McCann, Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester LE3 9QP, United Kingdom.
authors.forename: Iain B
authors.initials: IB
authors.lastname: Squire
authors.affiliation: Abhishek Shetye, Sheraz A Nazir, Iain B Squire, Gerald P McCann, Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester LE3 9QP, United Kingdom.
authors.forename: Gerald P
authors.initials: GP
authors.lastname: McCann
keywords: Feature tracking; Major adverse cardiac events; Myocardial infarction; Remodelling; Speckle tracking; Strain; Tagging