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The quest for load-independent left ventricular chamber properties: Exploring the normalized pressure phase plane

The pressure phase plane (PPP), defined by dP(t)/dt versus P(t) coordinates has revealed novel physiologic relationships not readily obtainable from conventional, time domain analysis of left ventricular pressure (LVP). We extend the methodology by introducing the normalized pressure phase plane (nP...

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Detalles Bibliográficos
Autores principales: Ghosh, Erina, Kovács, Sándor J
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Blackwell Publishing Ltd 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3834999/
https://www.ncbi.nlm.nih.gov/pubmed/24303128
http://dx.doi.org/10.1002/phy2.43
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author Ghosh, Erina
Kovács, Sándor J
author_facet Ghosh, Erina
Kovács, Sándor J
author_sort Ghosh, Erina
collection PubMed
description The pressure phase plane (PPP), defined by dP(t)/dt versus P(t) coordinates has revealed novel physiologic relationships not readily obtainable from conventional, time domain analysis of left ventricular pressure (LVP). We extend the methodology by introducing the normalized pressure phase plane (nPPP), defined by 0 ≤ P ≤ 1 and −1 ≤ dP/dt ≤ +1. Normalization eliminates load-dependent effects facilitating comparison of conserved features of nPPP loops. Hence, insight into load-invariant systolic and diastolic chamber properties and their coupling to load can be obtained. To demonstrate utility, high-fidelity P(t) data from 14 subjects (4234 beats) was analyzed. P(NR), the nPPP (dimensionless) pressure, where –dP/dt(peak) occurs, was 0.61 and had limited variance (7%). The relative load independence of P(NR) was corroborated by comparison of PPP and nPPP features of normal sinus rhythm (NSR) and (ejecting and nonejecting) premature ventricular contraction (PVC) beats. PVCs had lower P(t)(max) and lower peak negative and positive dP(t)/dt values versus NSR beats. In the nPPP, +dP/dt(peak) occurred at higher (dimensionless) P in PVC beats than in regular beats (0.44 in NSR vs. 0.48 in PVC). However, P(NR) for PVC versus NSR remained unaltered (P(NR) = 0.64; P > 0.05). Possible mechanistic explanation includes a (near) load-independent (constant) ratio of maximum cross-bridge uncoupling rate to instantaneous wall stress. Hence, nPPP analysis reveals LV properties obscured by load and by conventional temporal P(t) and dP(t)/dt analysis. nPPP identifies chamber properties deserving molecular and cellular physiologic explanation.
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spelling pubmed-38349992013-12-03 The quest for load-independent left ventricular chamber properties: Exploring the normalized pressure phase plane Ghosh, Erina Kovács, Sándor J Physiol Rep Original Research The pressure phase plane (PPP), defined by dP(t)/dt versus P(t) coordinates has revealed novel physiologic relationships not readily obtainable from conventional, time domain analysis of left ventricular pressure (LVP). We extend the methodology by introducing the normalized pressure phase plane (nPPP), defined by 0 ≤ P ≤ 1 and −1 ≤ dP/dt ≤ +1. Normalization eliminates load-dependent effects facilitating comparison of conserved features of nPPP loops. Hence, insight into load-invariant systolic and diastolic chamber properties and their coupling to load can be obtained. To demonstrate utility, high-fidelity P(t) data from 14 subjects (4234 beats) was analyzed. P(NR), the nPPP (dimensionless) pressure, where –dP/dt(peak) occurs, was 0.61 and had limited variance (7%). The relative load independence of P(NR) was corroborated by comparison of PPP and nPPP features of normal sinus rhythm (NSR) and (ejecting and nonejecting) premature ventricular contraction (PVC) beats. PVCs had lower P(t)(max) and lower peak negative and positive dP(t)/dt values versus NSR beats. In the nPPP, +dP/dt(peak) occurred at higher (dimensionless) P in PVC beats than in regular beats (0.44 in NSR vs. 0.48 in PVC). However, P(NR) for PVC versus NSR remained unaltered (P(NR) = 0.64; P > 0.05). Possible mechanistic explanation includes a (near) load-independent (constant) ratio of maximum cross-bridge uncoupling rate to instantaneous wall stress. Hence, nPPP analysis reveals LV properties obscured by load and by conventional temporal P(t) and dP(t)/dt analysis. nPPP identifies chamber properties deserving molecular and cellular physiologic explanation. Blackwell Publishing Ltd 2013-08 2013-08-22 /pmc/articles/PMC3834999/ /pubmed/24303128 http://dx.doi.org/10.1002/phy2.43 Text en © 2013 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society http://creativecommons.org/licenses/by/2.5/ Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.
spellingShingle Original Research
Ghosh, Erina
Kovács, Sándor J
The quest for load-independent left ventricular chamber properties: Exploring the normalized pressure phase plane
title The quest for load-independent left ventricular chamber properties: Exploring the normalized pressure phase plane
title_full The quest for load-independent left ventricular chamber properties: Exploring the normalized pressure phase plane
title_fullStr The quest for load-independent left ventricular chamber properties: Exploring the normalized pressure phase plane
title_full_unstemmed The quest for load-independent left ventricular chamber properties: Exploring the normalized pressure phase plane
title_short The quest for load-independent left ventricular chamber properties: Exploring the normalized pressure phase plane
title_sort quest for load-independent left ventricular chamber properties: exploring the normalized pressure phase plane
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3834999/
https://www.ncbi.nlm.nih.gov/pubmed/24303128
http://dx.doi.org/10.1002/phy2.43
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