title: Cardiovascular magnetic resonance-GUIDEd management of mild to moderate left ventricular systolic dysfunction (CMR GUIDE): Study protocol for a randomized controlled trial.
abstract: BACKGROUND
  The majority of sudden cardiac death (SCD) in patients with heart failure occurs in those with mild-moderate left ventricular (LV) systolic dysfunction (LVEF 36-50%) who under current guidelines are ineligible for primary prevention implantable cardiac defibrillator (ICD) therapy. Recent data suggest that cardiac magnetic resonance (CMR) evidence of replacement fibrosis forms a substrate for malignant arrhythmia and therefore potentially identifies a subgroup at increased risk of SCD. Our hypothesis is that among patients with mild-moderate LV systolic dysfunction, a CMR-guided management strategy for ICD insertion based on the presence of scar or fibrosis is superior to a current strategy of standard care.
  
  
  METHODS
  CMR GUIDE is a prospective, multicenter randomized control trial enrolling patients with mild-moderate LV systolic dysfunction and CMR evidence of fibrosis on optimal heart failure therapy. Participants will be randomized to receive either a primary prevention ICD or an implantable loop recorder (ILR). The primary endpoint is the time to SCD or hemodynamically significant ventricular arrhythmia (VF or VT) during an average 4-year follow-up. Secondary endpoints include quality of life assessed by Minnesota Living with Heart Failure Questionnaire, heart failure related hospitalizations, and a cost-utility analysis. Clinical trials.gov identifier NCT01918215.
  
  
  CONCLUSIONS
  CMR GUIDE trial will add substantially to our understanding of the role of myocardial fibrosis and the risk of developing life-threatening ventricular arrhythmias. If the superiority of a CMR-guided approach over standard care is proven, it may change international clinical guidelines, with the potential to considerably increase survival in this growing patient population.
authors.affiliation: Department of Cardiovascular Medicine, Flinders Medical Centre, Adelaide, SA, Australia.|School of Medicine, Flinders University, Adelaide, SA, Australia.|Department of Heart Health, South Australian Health & Medical Research Institute, Adelaide, SA, Australia.
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Selvanayagam
authors.affiliation: Department of Cardiovascular Medicine, Flinders Medical Centre, Adelaide, SA, Australia.|School of Medicine, Flinders University, Adelaide, SA, Australia.
authors.forename: Trent
authors.initials: T
authors.lastname: Hartshorne
authors.affiliation: The George Institute, Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
authors.forename: Laurent
authors.initials: L
authors.lastname: Billot
authors.affiliation: Department of Cardiovascular Medicine, Flinders Medical Centre, Adelaide, SA, Australia.|School of Medicine, Flinders University, Adelaide, SA, Australia.|Department of Heart Health, South Australian Health & Medical Research Institute, Adelaide, SA, Australia.
authors.forename: Suchi
authors.initials: S
authors.lastname: Grover
authors.affiliation: Royal Perth Hospital, Perth, WA, Australia.
authors.forename: Graham S
authors.initials: GS
authors.lastname: Hillis
authors.affiliation: Schwarzwald-Baar Klinikum, Villingen-Schwenningen, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Jung
authors.affiliation: Faculty of Medicine, Monash University, Clayton, VIC, Australia.
authors.forename: Henry
authors.initials: H
authors.lastname: Krum
authors.affiliation: Royal Brompton Hospital, London, England.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Prasad
authors.affiliation: Department of Cardiovascular Medicine, Flinders Medical Centre, Adelaide, SA, Australia.|School of Medicine, Flinders University, Adelaide, SA, Australia.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: McGavigan
mesh_terms: D000328:Adult; D001315:Australia; D017147:Defibrillators, Implantable; D005060:Europe; D005260:Female; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008297:Male; D010138:Pacemaker, Artificial; D012042:Registries; D012720:Severity of Illness Index; D018487:Ventricular Dysfunction, Left / Q000628:therapy*; D055815:Young Adult
keywords: cardiac magnetic resonance imaging; implantable cardiac defibrillator; left ventricular systolic dysfunction; sudden cardiac death; syncope