Factors that Regulate Transmural Myocardial Blood Flow Distribution

Abstract

This chapter describes the mechanical factors that regulate transmural myocardial blood flow distribution in hearts (a) with normal coronary circulation, (b) with coronary stenosis, and (c) in those having functional collateral vasculature. The control of coronary vasomotion during normal and pathologic states by both metabolic and neurogenic mechanisms is not discussed. In the past five years, there have been two excellent review articles [1,2] and one monograph [3] that describe in detail the coronary circulation. The reader is referred to these sources for material not covered in this chapter. The physiologic data presented will be of necessity from animal models, but the principles outlined probably are applicable to the human coronary circulation. The importance of perfusion pressure in maintaining transmural myocardial blood flow distribution will be emphasized. The factors that make the endocardial layers especially vulnerable to hypoperfusion will be stressed.