TY - JOUR
T1 - Thermodynamic phase plane analysis of ventricular contraction and relaxation
AU - Karamanoglu, Mustafa
AU - Kovács, Sándor J.
PY - 2004/3/5
Y1 - 2004/3/5
N2 - Background: Ventricular function has conventionally been characterized using indexes of systolic (contractile) or diastolic (relaxation/stiffness) function. Systolic indexes include maximum elastance or equivalently the end-systolic pressure volume relation and left ventricular ejection fraction. Diastolic indexes include the time constant of isovolumic relaxation - and the end-diastolic pressure-volume relation. Conceptualization of ventricular contraction/relaxation coupling presents a challenge when mechanical events of the cardiac cycle are depicted in conventional pressure, P, or volume, V, terms. Additional conceptual difficulty arises when ventricular/vascular coupling is considered using P, V variables. Methods: We introduce the concept of thermodynamic phase-plane, TPP, defined by the PdV and VdP axes. Results: TPP allows all cardiac mechanical events and their coupling to the vasculature to be geometrically depicted and simultaneously analyzed. Conclusion: Conventional systolic and diastolic function indexes are easily recovered and novel indexes of contraction-relaxation coupling are discernible.
AB - Background: Ventricular function has conventionally been characterized using indexes of systolic (contractile) or diastolic (relaxation/stiffness) function. Systolic indexes include maximum elastance or equivalently the end-systolic pressure volume relation and left ventricular ejection fraction. Diastolic indexes include the time constant of isovolumic relaxation - and the end-diastolic pressure-volume relation. Conceptualization of ventricular contraction/relaxation coupling presents a challenge when mechanical events of the cardiac cycle are depicted in conventional pressure, P, or volume, V, terms. Additional conceptual difficulty arises when ventricular/vascular coupling is considered using P, V variables. Methods: We introduce the concept of thermodynamic phase-plane, TPP, defined by the PdV and VdP axes. Results: TPP allows all cardiac mechanical events and their coupling to the vasculature to be geometrically depicted and simultaneously analyzed. Conclusion: Conventional systolic and diastolic function indexes are easily recovered and novel indexes of contraction-relaxation coupling are discernible.
KW - Contraction/relaxation coupling
KW - Diastolic function
KW - Pressure-volume loops
KW - Ventricular function
UR - http://www.scopus.com/inward/record.url?scp=3042599023&partnerID=8YFLogxK
U2 - 10.1186/1475-925X-3-6
DO - 10.1186/1475-925X-3-6
M3 - Article
C2 - 15003127
AN - SCOPUS:3042599023
VL - 3
JO - BioMedical Engineering Online
JF - BioMedical Engineering Online
SN - 1475-925X
M1 - 6
ER -