Coronary microcirculation in the beating heart.
The phase opposition of velocity waveforms between coronary arteries (predominantly diastolic) and veins (systolic) is the most prominent characteristic of coronary hemodynamics. This unique arterial and venous flow patterns indicate the importance of intramyocardial capacitance vessels and variable resistance vessels during a cardiac cycle. It was shown that during diastole the intramyocardial capacitance vessels have two functional components, unstressed volume and ordinary capacitance. Unstressed volume is defined as the volume of blood in a vessel at zero transmural pressure. In vivo observation of systolic narrowing of arterioles in mid-wall and in subendocardium indicates the increase in resistance by cardiac contraction.
Kajiya
Fumihiko
F
Department of Medical Engineering, Kawasaki Medical School, 288 Matsushima Kurashiki, Okayama 701-0193, Japan. kajiya@me.kawasaki-m.ac.jp
Yada
Toyotaka
T
Hiramatsu
Osamu
O
Ogasawara
Yasuo
Y
Inai
Yousuke
Y
Kajiya
Masahito
M
D001783:Blood Flow Velocity / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008833:Microcirculation / Q000502:physiology*; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000502:physiology*; D014655:Vascular Resistance / Q000502:physiology