title: Diastolic function assessed from tagged MRI predicts heart failure and atrial fibrillation over an 8-year follow-up period: the multi-ethnic study of atherosclerosis.
abstract: OBJECTIVE
  The strain relaxation index (SRI), a novel diastolic functional parameter derived from tagged magnetic resonance imaging (MRI), is used to assess myocardial deformation during left ventricular relaxation. We investigated whether diastolic function indexed by SRI predicts heart failure (HF) and atrial fibrillation (AF) over an 8-year follow-up.
  
  
  METHODS
  As a part of the multi-ethnic study of atherosclerosis, 1544 participants free of known cardiovascular disease (CVD) underwent tagged MRI in 2000-02. Harmonic phase analysis was used to compute circumferential strain. Standard parameters, early diastolic strain rate (EDSR) and the peak torsion recoil rate were calculated. An SRI was calculated as difference between post-systolic and systolic times of the strain peaks, divided by the EDSR peak. It was normalized by the total interval of relaxation. Over an 8-year follow-up period, we defined AF (n = 57) or HF (n = 36) as combined (n = 80) end-points. Cox regression assessed the ability of SRI to predict events adjusted for risk factors and markers of subclinical disease. Integrated discrimination index (IDI) and net reclassification index (NRI) of SRI, compared with conventional indices, were also assessed.
  
  
  RESULTS
  The hazard ratio for SRI remained significant for the combined HF and AF end-points as well as for HF alone after adjustment. For the combined end-point, IDI was 1.5% (P < 0.05) and NRI was 11.4% (P < 0.05) for SRI. Finally, SRI was more robust than all other existing cardiovascular magnetic resonance diastolic functional parameters.
  
  
  CONCLUSIONS
  SRI predicts HF and AF over an 8-year follow-up period in a large population free of known CVD, independent of established risk factors and markers of subclinical CVD.
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Bharath
authors.initials: B
authors.lastname: Ambale-Venkatesh
authors.forename: Anderson C
authors.initials: AC
authors.lastname: Armstrong
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Liu
authors.forename: Sirisha
authors.initials: S
authors.lastname: Donekal
authors.forename: Kihei
authors.initials: K
authors.lastname: Yoneyama
authors.forename: Colin O
authors.initials: CO
authors.lastname: Wu
authors.forename: Antoinette S
authors.initials: AS
authors.lastname: Gomes
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Hundley
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
authors.forename: Joao A
authors.initials: JA
authors.lastname: Lima
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*; D001938:Brazil; D003971:Diastole; D005006:Ethnicity; D005260:Female; D005500:Follow-Up Studies; D054144:Heart Failure, Diastolic / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014481:United States
keywords: Atrial; Diastole; Fibrillation; Heart failure; Magnetic resonance imaging