Left ventricular wall stress normalization in chronic pressure-overloaded heart: A mathematical model study
article
It is generally accepted that the left ventricle (LV) hypertrophies (LVH) to normalize systolic wall stress (σ(s)) in chronic pressure overload. However, LV filling pressure (P(v)) may be elevated as well, supporting the alternative hypothesis of end-diastolic wall stress (σ(d)) normalization in LVH. We used an LV time-varying elastance model coupled to an arterial four-element lumped-parameter model to study ventriculararterial interaction in hypertension-induced LVH. We assessed model parameters for normotensive controls and applied arterial changes as observed in hypertensive patients with LVH (resistance +40%, compliance -25%) and assumed 1) no cardiac adaptation, 2) normalization of σ(s) by LVH, and 3) normalization of σ(s) by LVH and increase in P(v), such that σ(d) is normalized as well. In patients, systolic and diastolic blood pressures increase by ~40%, cardiac output (CO) is constant, and wall thickness increases by 30-55%. In scenarios 1 and 2, blood pressure increased by only 10% while CO dropped by 20%. In scenario 2, LV wall thickness increased by only 10%. The predictions of scenario 3 were in qualitative and quantitative agreement with in vivo human data. LVH thus contributes to the elevated blood pressure in hypertension, and cardiac adaptations include an increase in P(v), normalization of σ(s), and preservation of CO in the presence of an impaired diastolic function.
Topics
AgingHeart-arterial interactionVarying elastanceWindkesselArteryHeart left ventricle enddiastolic pressureHeart left ventricle filling pressureHeart left ventricle hypertrophyHeart left ventricle overloadHeart outputHeart ventricle complianceMathematical modelPredictionAdaptation, PhysiologicalBlood PressureCardiac OutputChronic DiseaseComputer SimulationDiastoleHumansHypertensionHypertrophy, Left VentricularModels, CardiovascularReproducibility of ResultsStress, MechanicalSystole
TNO Identifier
235700
ISSN
03636135
Source
American Journal of Physiology - Heart and Circulatory Physiology, 279(3 48-3)
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