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Closing the loop: modelling of heart failure progression from health to end-stage using a meta-analysis of left ventricular pressure-volume loops.

Warriner DR, Brown AG, Varma S, Sheridan PJ, Lawford P, Hose DR, Al-Mohammad A, Shi Y - PLoS ONE (2014)

Bottom Line: The only parameter that was consistently and statistically different across all the stages was the elastance (Emax).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.

View Article: PubMed Central - PubMed

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.

ABSTRACT

Introduction: 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.

Methods and 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.

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Related in: MedlinePlus

Screenshot from Engauge - on the left, the pressure volume loop is seen, with red cross hairs denoting X and Y axes, and blue crosshairs which correspond with the numerical values of pressure and volume seen in the table on the right.LV  =  left ventricle.
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pone-0114153-g003: Screenshot from Engauge - on the left, the pressure volume loop is seen, with red cross hairs denoting X and Y axes, and blue crosshairs which correspond with the numerical values of pressure and volume seen in the table on the right.LV  =  left ventricle.

Mentions: Engauge digitizing software (http://digitizer.sourceforge.net/) was then used to upload the graphical PV loop images from the original studies and convert them into numerical data, as seen in figure 3[39]. This freeware allows users to upload a graphical image, such as a PV loop, in variety of formats such as a Joint Photographic Experts Group (JPEG) file, and convert a pictorial image into numerical data. After loading the file, the parameters of the axes (red crosshairs) were chosen, with X corresponding to 80–280 ml and Y 0–150 mmHg respectively. The PV loop is then digitised automatically (blue crosshairs), turning the PV loop picture into a series of individual pressure and volume data points, 10 points per limb of the curve, giving a total of 40 data points for each PV loop. The LV PV loops from each LVSD-HF stage were converted into digital values and these were then tabulated and the mean for each calculated.


Closing the loop: modelling of heart failure progression from health to end-stage using a meta-analysis of left ventricular pressure-volume loops.

Warriner DR, Brown AG, Varma S, Sheridan PJ, Lawford P, Hose DR, Al-Mohammad A, Shi Y - PLoS ONE (2014)

Screenshot from Engauge - on the left, the pressure volume loop is seen, with red cross hairs denoting X and Y axes, and blue crosshairs which correspond with the numerical values of pressure and volume seen in the table on the right.LV  =  left ventricle.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257583&req=5

pone-0114153-g003: Screenshot from Engauge - on the left, the pressure volume loop is seen, with red cross hairs denoting X and Y axes, and blue crosshairs which correspond with the numerical values of pressure and volume seen in the table on the right.LV  =  left ventricle.
Mentions: Engauge digitizing software (http://digitizer.sourceforge.net/) was then used to upload the graphical PV loop images from the original studies and convert them into numerical data, as seen in figure 3[39]. This freeware allows users to upload a graphical image, such as a PV loop, in variety of formats such as a Joint Photographic Experts Group (JPEG) file, and convert a pictorial image into numerical data. After loading the file, the parameters of the axes (red crosshairs) were chosen, with X corresponding to 80–280 ml and Y 0–150 mmHg respectively. The PV loop is then digitised automatically (blue crosshairs), turning the PV loop picture into a series of individual pressure and volume data points, 10 points per limb of the curve, giving a total of 40 data points for each PV loop. The LV PV loops from each LVSD-HF stage were converted into digital values and these were then tabulated and the mean for each calculated.

Bottom Line: The only parameter that was consistently and statistically different across all the stages was the elastance (Emax).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.

View Article: PubMed Central - PubMed

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.

ABSTRACT

Introduction: 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.

Methods and 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.

Show MeSH
Related in: MedlinePlus