title: Left ventricular fluid kinetic energy time curves in heart failure from cardiovascular magnetic resonance 4D flow data.
abstract: BACKGROUND
  Measurement of intracardiac kinetic energy (KE) provides new insights into cardiac hemodynamics and may improve assessment and understanding of heart failure. We therefore aimed to investigate left ventricular (LV) KE time curves in patients with heart failure and in controls.
  
  
  METHODS
  Patients with heart failure (n = 29, NYHA class I-IV) and controls (n = 12) underwent cardiovascular magnetic resonance (CMR) including 4D flow. The vortex-ring boundary was computed using Lagrangian coherent structures. The LV endocardium and vortex-ring were manually delineated and KE was calculated as ½mv(2) of the blood within the whole LV and the vortex ring, respectively.
  
  
  RESULTS
  The systolic average KE was higher in patients compared to controls (2.2 ± 1.4 mJ vs 1.6 ± 0.6 mJ, p = 0.048), but lower when indexing to EDV (6.3 ± 2.2 μJ/ml vs 8.0 ± 2.1 μJ/ml, p = 0.025). No difference was seen in diastolic average KE (3.2 ± 2.3 mJ vs 2.0 ± 0.8 mJ, p = 0.13) even when indexing to EDV (9.0 ± 4.4 μJ/ml vs 10.2 ± 3.3 μJ/ml, p = 0.41). In patients, a smaller fraction of diastolic average KE was observed inside the vortex ring compared to controls (72 ± 6% vs 54 ± 9%, p < 0.0001). Three distinctive KE time curves were seen in patients which were markedly different from findings in controls, and with a moderate agreement between KE time curve patterns and degree of diastolic dysfunction (Cohen's kappa = 0.49), but unrelated to NYHA classification (p = 0.12), or 6-minute walk test (p = 0.72).
  
  
  CONCLUSIONS
  Patients with heart failure exhibit higher systolic average KE compared to controls, suggesting altered intracardiac blood flow. The different KE time curves seen in patients may represent a conceptually new approach for heart failure classification.
authors.affiliation: Department of Clinical Physiology, Clinical Sciences, Lund University, Lund University Hospital, Lund, Sweden. mikael.kanski@med.lu.se.
authors.forename: Mikael
authors.initials: M
authors.lastname: Kanski
authors.affiliation: Department of Clinical Physiology, Clinical Sciences, Lund University, Lund University Hospital, Lund, Sweden. per.arvidsson@med.lu.se.
authors.forename: Per M
authors.initials: PM
authors.lastname: Arvidsson
authors.affiliation: Department of Clinical Physiology, Clinical Sciences, Lund University, Lund University Hospital, Lund, Sweden. johannes.toger@gmail.com.
authors.forename: Johannes
authors.initials: J
authors.lastname: Töger
authors.affiliation: Department of Cardiology, Clinical Sciences, Lund University, Lund University Hospital, Lund, Sweden. rasmus.borgquist@med.lu.se.
authors.forename: Rasmus
authors.initials: R
authors.lastname: Borgquist
authors.affiliation: Department of Clinical Physiology, Clinical Sciences, Lund University, Lund University Hospital, Lund, Sweden. einar.heiberg@med.lu.se.|Department of Biomedical Engineering, Faculty of Engineering, Lund University, Lund, Sweden. einar.heiberg@med.lu.se.|Centre for Mathematical Sciences, Faculty of Engineering, Lund University, Lund, Sweden. einar.heiberg@med.lu.se.
authors.forename: Einar
authors.initials: E
authors.lastname: Heiberg
authors.affiliation: Department of Clinical Physiology, Clinical Sciences, Lund University, Lund University Hospital, Lund, Sweden. marcus.carlsson@med.lu.se.
authors.forename: Marcus
authors.initials: M
authors.lastname: Carlsson
authors.affiliation: Department of Clinical Physiology, Clinical Sciences, Lund University, Lund University Hospital, Lund, Sweden. hakan.arheden@med.lu.se.
authors.forename: Håkan
authors.initials: H
authors.lastname: Arheden
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D003326:Coronary Circulation; D003971:Diastole; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007700:Kinetics; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012039:Regional Blood Flow; D012720:Severity of Illness Index; D013599:Systole; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000503:physiopathology; D016277:Ventricular Function, Left; D055815:Young Adult