Faculty Collaboration Database

Modeling to link regional myocardial work, metabolism and blood flows. Ann Biomed Eng 2012 Nov;40(11):2379-98

Date

08/24/2012

Pubmed ID

22915334

Pubmed Central ID

PMC3471663

DOI

10.1007/s10439-012-0613-5

Scopus ID

2-s2.0-84868354496 (requires institutional sign-in at Scopus site)   12 Citations

Abstract

Given the mono-functional, highly coordinated processes of cardiac excitation and contraction, the observations that regional myocardial blood flows, rMBF, are broadly heterogeneous has provoked much attention, but a clear explanation has not emerged. In isolated and in vivo heart studies the total coronary flow is found to be proportional to the rate-pressure product (systolic mean blood pressure times heart rate), a measure of external cardiac work. The same relationship might be expected on a local basis: more work requires more flow. The validity of this expectation has never been demonstrated experimentally. In this article we review the concepts linking cellular excitation and contractile work to cellular energetics and ATP demand, substrate utilization, oxygen demand, vasoregulation, and local blood flow. Mathematical models of these processes are now rather well developed. We propose that the construction of an integrated model encompassing the biophysics, biochemistry and physiology of cardiomyocyte contraction, then combined with a detailed three-dimensional structuring of the fiber bundle and sheet arrangements of the heart as a whole will frame an hypothesis that can be quantitatively evaluated to settle the prime issue: Does local work drive local flow in a predictable fashion that explains the heterogeneity? While in one sense one can feel content that work drives flow is irrefutable, the are no cardiac contractile models that demonstrate the required heterogeneity in local strain-stress-work; quite the contrary, cardiac contraction models have tended toward trying to show that work should be uniform. The object of this review is to argue that uniformity of work does not occur, and is impossible in any case, and that further experimentation and analysis are necessary to test the hypothesis.

Author List

Bassingthwaighte JB, Beard DA, Carlson BE, Dash RK, Vinnakota K

Author

Ranjan K. Dash PhD Professor in the Biomedical Engineering department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Coronary Circulation
Heart
Hemoglobins
Humans
Models, Cardiovascular
Myocardium
Oxygen