scholarly journals EFFECT OF ATRIAL FIBRILLATION ON CORONARY CIRCULATION AND BLOOD FLOW DISTRIBUTION ACROSS THE LEFT VENTRICULAR WALL IN ANESIHETIZED OPEN-CHEST DOGS

1978 ◽  
Vol 42 (4) ◽  
pp. 417-423 ◽  
Author(s):  
DAIJI SAITO ◽  
SHOICHI HARAOKA ◽  
MINORU UEDA ◽  
TOSHIO FUJIMOTO ◽  
HIDENORI YOSHIDA ◽  
...  
1988 ◽  
Vol 255 (3) ◽  
pp. H664-H672 ◽  
Author(s):  
Y. Sun ◽  
H. Gewirtz

To characterize the intramyocardial pressure (IMP) and coronary blood flow distribution in a stenosed coronary circulation, we compared four analog circuits for modeling coronary impedance. The resistor (R)-diode (D) model simulates vascular collapse, and the capacitor (C) simulates compliance effect. Identification of the best model and magnitudes of the endocardial and epicardial IMPs (IMPendo and IMPepi) was done retrospectively using data from studies in 28 anesthetized swine. Performance evaluation was based on comparison of model predicted vs. observed coronary distal pressure (DP) waveforms and endocardial-to-epicardial (endo-epi) flow ratios as determined by radiolabeled microspheres. The R-D-C model gave the best performance at IMPendo = 1.1 times left ventricular pressure (LVP), and IMPepi = 0.1.LVP + 15 mmHg; with good fit to DP (r = 0.98, slope of regression line = 1.0) and estimates of endo-epi flow ratio (r = 0.78, slope = 1.01, P less than 0.02, SEE = 0.21, n = 139). The R-D model gave comparable results even though capacitance was omitted. Although R-C and R models predicted distal coronary pressure well, they failed to predict endo-epi flow ratios (r less than 0.50). The R-D-C and R-D models were applied in seven prospective studies. Both models generated reasonable estimates of endo-epi flow distribution (r = 0.78, n = 50). Thus the R-D-C or R-D models of the stenosed coronary circulation can be used to provide reliable estimates of transmural blood flow distribution.


1985 ◽  
Vol 249 (2) ◽  
pp. H337-H343 ◽  
Author(s):  
J. V. Reid ◽  
B. R. Ito ◽  
A. H. Huang ◽  
C. W. Buffington ◽  
E. O. Feigl

The transmural distribution of coronary blood flow was studied during vagal stimulation in closed-chest, morphine- and alpha-chloralose-anesthetized dogs. The left main coronary artery was cannulated and perfused at constant pressure. Bradycardia during vagal stimulation was prevented by atrioventricular heart block and ventricular pacing. Beta-adrenergic receptors were blocked with propranolol (1 mg/kg iv), and aortic pressure was stabilized by means of a pressure reservoir. Regional myocardial blood flow was measured with 9-micron radioactive microspheres during vagal stimulation and during intracoronary acetylcholine infusion. Vagal stimulation increased coronary blood flow uniformly across the left ventricular wall. In contrast, intracoronary acetylcholine infusion, at a rate selected to increase total flow to the same degree, vasodilated the subendocardium more than the subepicardium, increasing the inner/outer blood flow ratio. It is concluded that both vagal activation and acetylcholine produce coronary vasodilation that is independent of left ventricular preload, afterload, and heart rate. Acetylcholine vasodilation preferentially vasodilates the subendocardium, increasing the inner/outer flow ratio, but vagal stimulation produces uniform vasodilation across the left ventricular wall.


1977 ◽  
Vol 72 (5) ◽  
pp. 479-491 ◽  
Author(s):  
M. Nakamura ◽  
H. Matsuguchi ◽  
A. Mitsutake ◽  
Y. Kikuchi ◽  
A. Takeshita ◽  
...  

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