title: Closing the loop: modelling of heart failure progression from health to end-stage using a meta-analysis of left ventricular pressure-volume loops.
abstract: BACKGROUND
  The American Heart Association (AHA)/American College of Cardiology (ACC) guidelines for the classification of heart failure (HF) are descriptive but lack precise and objective measures which would assist in categorising such patients. Our aim was two fold, firstly to demonstrate quantitatively the progression of HF through each stage using a meta-analysis of existing left ventricular (LV) pressure-volume (PV) loop data and secondly use the LV PV loop data to create stage specific HF models.
  
  
  RESULTS
  A literature search yielded 31 papers with PV data, representing over 200 patients in different stages of HF. The raw pressure and volume data were extracted from the papers using a digitising software package and the means were calculated. The data demonstrated that, as HF progressed, stroke volume (SV), ejection fraction (EF%) decreased while LV volumes increased. A 2-element lumped parameter model was employed to model the mean loops and the error was calculated between the loops, demonstrating close fit between the loops. The only parameter that was consistently and statistically different across all the stages was the elastance (Emax).
  
  
  CONCLUSIONS
  For the first time, the authors have created a visual and quantitative representation of the AHA/ACC stages of LVSD-HF, from normal to end-stage. The study demonstrates that robust, load-independent and reproducible parameters, such as elastance, can be used to categorise and model HF, complementing the existing classification. The modelled PV loops establish previously unknown physiological parameters for each AHA/ACC stage of LVSD-HF, such as LV elastance and highlight that it this parameter alone, in lumped parameter models, that determines the severity of HF. Such information will enable cardiovascular modellers with an interest in HF, to create more accurate models of the heart as it fails.
authors.affiliation: Medical Physics Group, Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2TN, United Kingdom; Department of Cardiology, Northern General Hospital, Sheffield Teaching Hospitals, Sheffield, S5 7AU, United Kingdom.
authors.forename: David R
authors.initials: DR
authors.lastname: Warriner
authors.affiliation: Medical Physics Group, Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
authors.forename: Alistair G
authors.initials: AG
authors.lastname: Brown
authors.affiliation: Medical Physics Group, Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
authors.forename: Susheel
authors.initials: S
authors.lastname: Varma
authors.affiliation: Medical Physics Group, Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2TN, United Kingdom; Department of Cardiology, Northern General Hospital, Sheffield Teaching Hospitals, Sheffield, S5 7AU, United Kingdom.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Sheridan
authors.affiliation: Medical Physics Group, Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
authors.forename: Patricia
authors.initials: P
authors.lastname: Lawford
authors.affiliation: Medical Physics Group, Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
authors.forename: David R
authors.initials: DR
authors.lastname: Hose
authors.affiliation: Department of Cardiology, Northern General Hospital, Sheffield Teaching Hospitals, Sheffield, S5 7AU, United Kingdom.
authors.forename: Abdallah
authors.initials: A
authors.lastname: Al-Mohammad
authors.affiliation: Medical Physics Group, Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
authors.forename: Yubing
authors.initials: Y
authors.lastname: Shi
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D018450:Disease Progression; D006333:Heart Failure / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D013318:Stroke Volume / Q000502:physiology; D013599:Systole / Q000502:physiology; D014481:United States; D017725:Ventricular Pressure / Q000502:physiology*