title: Left and right atrial feature tracking in acute myocarditis: A feasibility study.
abstract: OBJECTIVE
  The present study aims at evaluating the feasibility and reproducibility of cardiac magnetic resonance (CMR) feature tracking (FT) derived strain and strain rate (SR) parameters of the left and right atrium (LA, RA) in patients with acute myocarditis as well as their potential to detect diastolic dysfunction. In addition, the diagnostic value of LA and RA strain parameters in the setting of acute myocarditis is investigated.
  
  
  METHODS
  CMR cine data of 30 patients with CMR-positive acute myocarditis were retrospectively analyzed. 25 age- and gender-matched healthy individuals served as a control. Analysis of longitudinal strain and SR of both atria was performed in two long-axis views using a dedicated FT-software. LA and RA deformation was analyzed including reservoir function (total strain [εs], peak positive SR [SRs]), conduit function (passive strain [εe], peak early negative SR [SRe]) and booster pump function (active strain [εa], peak late negative SR [SRa]). Intra- and inter-observer reproducibility was assessed for all strain and SR parameters using Bland-Altman analyses, intra-class correlation coefficients (ICCs) and coefficients of variation (CV).
  
  
  RESULTS
  FT analyses of both atria were feasible in all patients and controls. Reproducibility was good for reservoir and conduit function parameters and moderate for booster pump function parameters. Myocarditis patients demonstrated an impaired LA reservoir and conduit function when compared to healthy controls (LA εs: 32±17 vs. 46±13, p=0.019; LA SRs: 1.5±0.5 vs. 1.8±0.5, p=0.117; LA SRe: -1.3±0.5 vs. -1.9±0.5, p<0.001), while LA booster pump function was preserved. In logistic regression and ROC-analyses, LA SReproved to be the best independent predictor of acute myocarditis (AUC 0.80), and using LA SRewith a cut-off of -1.6s-1resulted in a diagnostic sensitivity of 83% and a specificity of 80%. Changes in RA phasic function parameters showed a tendency to parallel those of the LA and showed no additional effect with respect to the diagnostic potential in acute myocarditis.
  
  
  CONCLUSIONS
  Myocarditis patients exhibit an impaired atrial reservoir and conduit function, what might be indicative of ventricular diastolic dysfunction. LA SRewas the best predictor for the presence of acute myocarditis in our study, pointing towards the discriminative power of atrial strain analysis in the CMR-based diagnosis of acute myocarditis.
authors.affiliation: Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany. Electronic address: anastasia-dick@web.de.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Dick
authors.affiliation: Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany. Electronic address: bjoernschmidt1989@gmx.de.
authors.forename: Björn
authors.initials: B
authors.lastname: Schmidt
authors.affiliation: Department III of Internal Medicine, Heart Centre, University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany. Electronic address: guido.michels@uk-koeln.de.
authors.forename: Guido
authors.initials: G
authors.lastname: Michels
authors.affiliation: Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany. Electronic address: alexander.bunck@uk-koeln.de.
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Bunck
authors.affiliation: Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany. Electronic address: david.maintz@uk-koeln.de.
authors.forename: David
authors.initials: D
authors.lastname: Maintz
authors.affiliation: Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany. Electronic address: bettina.baessler@uk-koeln.de.
authors.forename: Bettina
authors.initials: B
authors.lastname: Baeßler
mesh_terms: D000328:Adult; D020517:Atrial Appendage / Q000473:pathology / Q000503:physiopathology; D016279:Atrial Function, Left / Q000502:physiology; D003971:Diastole / Q000502:physiology; D004452:Echocardiography / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D006325:Heart Atria / Q000473:pathology; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods; D008297:Male; D008875:Middle Aged; D009205:Myocarditis / Q000503:physiopathology*; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012984:Software; D013314:Stress, Mechanical; D013312:Stress, Physiological / Q000502:physiology; D018754:Ventricular Dysfunction / Q000175:diagnosis* / Q000503:physiopathology
keywords: Acute myocarditis; Atrial strain; Cardiovascular magnetic resonance; Diastolic dysfunction; Feature tracking