Influence of timing and magnitude of arterial wave reflection on left ventricular relaxation.
The influence of timing and magnitude of arterial wave reflection (WR) on afterload-dependent relaxation was evaluated in patients with a variety of heart diseases (group 1, age < 30 yr; group 2, age > 40 yr) and in dogs. While both femoral arteries were compressed (FC), WR returned just after the dicrotic notch (early diastole) in group 1 but before the dicrotic notch (late systole) in group 2. The time constant of the left ventricular pressure decay (tau) was shortened during FC in group 1, whereas it was prolonged in group 2. In dogs, a constriction of the thoracic aorta induced a late systolic augmentation of WR with a prolongation of tau (cf. group 2), whereas constriction of the lower abdominal aorta induced an early diastolic augmentation of WR with a shortening of tau (cf. group 1). With aortic constriction, coronary flow increased, and there was a close correlation between the peak change in backward aortic pressure and that in coronary flow regardless of the timing of WR. Thus the time at which WR returns during the cardiac cycle may have an important effect on left ventricular relaxation and coronary flow.
Second Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Yamaguchi 755-8505, Japan. yanoma@po.cc.yamaguchi-u.ac.jp
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M
Yano
M
M
Kohno
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S
Kobayashi
M
M
Obayashi
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K
Seki
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Ohkusa
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T
Miura
T
T
Fujii
M
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Matsuzaki
D000328:Adult; D000368:Aged; D000818:Animals; D001012:Aorta, Abdominal / Q000502:physiology; D001013:Aorta, Thoracic / Q000502:physiology; D001794:Blood Pressure; D003326:Coronary Circulation / Q000502:physiology; D003327:Coronary Disease / Q000503:physiopathology*; D004285:Dogs; D005263:Femoral Artery / Q000502:physiology / Q000503:physiopathology*; D006331:Heart Diseases / Q000503:physiopathology*; D006339:Heart Rate; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D011674:Pulse; D012044:Regression Analysis; D014661:Vasoconstriction; D016277:Ventricular Function, Left / Q000502:physiology*