Measurement of Intramyocardial Pressure in the Left Ventricular Wall of Isolated Rabbit Heart.

The endothelium plays a critical role in maintaining vascular tone by releasing nitric oxide (NO). Endothelium derived NO diffuses to smooth muscles, triggering their relaxation. The dynamic of NO production is a determining factor in signal transduction. The present studies were designed to elucidate dynamics of NO release from normal and dysfunctional endothelium. The nanosensors (diameter 100-300 nm) exhibiting a response time better than 100 micros and detection limit of 1.0 x 10(-9) mol L(-1) were used for in vitro monitoring of NO release from single endothelial cells from the iliac artery of normotensive (WKY) rats, hypertensive (SHR) rats, and normal and cholesterolemic rabbits. Also, the dynamics and distribution of NO in left ventricular wall of rabbit heart were measured. The rate of NO release was much higher (1200 +/- 50 nmol L(-1) s(-1)) for WKY than for SHR (460 +/- 10 nmol L(-1) s(-1)). Also, the peak NO concentration was about three times higher for WKY than SHR. Similar decrease in the dynamics of NO release was observed for cholesterolemic rabbits. The dynamics of NO release changed dramatically along the wall of rabbit aorta, being highest (0.86 +/- 0.12 micromol L(-1)) for the ascending aorta, and lowest for the iliac aorta (0.48 +/- 0.15 micromol L(-1)). The distribution of NO in the left ventricular wall of rabbit heart was not uniform and varied from 1.23 +/- 0.20 micromol L(-1) (center) to 0.90 +/- 0.15 micromol L(-1) (apex). Both, the maximal concentration and the dynamics of NO release can be useful diagnostic tools in estimating the level of endothelial dysfunction and cardiovascular system efficiency.

Download Full-text

Comparison of the distribution of intramyocardial pressure across the canine left ventricular wall in the beating heart during diastole and in the arrested heart. Evidence of epicardial muscle tone during diastole.

Circulation Research ◽

10.1161/01.res.47.2.258 ◽

1980 ◽

Vol 47 (2) ◽

pp. 258-267 ◽

Cited By ~ 31

Author(s):

P D Stein ◽

H N Sabbah ◽

M Marzilli ◽

E F Blick

Keyword(s):

Muscle Tone ◽

Left Ventricular ◽

Beating Heart ◽

Left Ventricular Wall ◽

Ventricular Wall ◽

Intramyocardial Pressure

Download Full-text

An experimental and theoretical analysis of myocardial tissue pressure

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1964.207.2.361 ◽

1964 ◽

Vol 207 (2) ◽

pp. 361-367 ◽

Cited By ~ 142

Author(s):

Edward S. Kirk ◽

Carl R. Honig

Keyword(s):

Theoretical Analysis ◽

Left Ventricular ◽

Left Ventricular Wall ◽

Coronary Vessel ◽

Myocardial Tissue ◽

Ventricular Wall ◽

Tissue Pressure ◽

Intramyocardial Pressure ◽

Flow Through ◽

A New Technique

A new technique for estimating myocardial tissue pressure is described. The method is based upon changes in flow through an analog of a small coronary vessel. A gradient of tissue pressure from epicardium to endocardium was observed with peak tissue pressures twice peak ventricular pressure recorded in the inner half of the wall. A theoretical analysis of the concept of intramyocardial pressure is presented, based on the assumption that the tissue is a solid within which both longitudinal and radial compressive forces exist. The similarity between the gradient of longitudinal tissue pressure predicted by the theoretical analysis and the gradient experimentally determined suggests that the latter describes the maximum pressures which exist in the left ventricular wall.

Download Full-text

Clinical and Experimental Analysis of 201Thallium Uptake of the Heart

Nuklearmedizin ◽

10.1055/s-0037-1620682 ◽

1978 ◽

Vol 17 (04) ◽

pp. 142-148

Author(s):

U. Büll ◽

S. Bürger ◽

B. E. Strauer

Keyword(s):

Oxygen Consumption ◽

Left Ventricle ◽

Muscle Mass ◽

Myocardial Oxygen Consumption ◽

Animal Experiments ◽

Left Ventricular ◽

Left Ventricular Wall ◽

Ventricular Wall ◽

Flow Measurements ◽

Myocardial Flow

Studies were carried out in order to determine the factors influencing myocardial 201T1 uptake. A total of 158 patients was examined with regard to both 201T1 uptake and the assessment of left ventricular and coronary function (e. g. quantitative ventriculography, coronary arteriography, coronary blood flow measurements). Moreover, 42 animal experiments (closed chest cat) were performed. The results demonstrate that:1) 201T1 uptake in the normal and hypertrophied human heart is linearly correlated with the muscle mass of the left ventricle (LVMM);2) 201T1 uptake is enhanced in the inner (subendocardial) layer and is decreased in the outer (subepicardial) layer of the left ventricular wall. The 201T1 uptake of the right ventricle is 40% lower in comparison to the left ventricle;3) the basic correlation between 201T1 uptake and LVMM is influenced by alterations of both myocardial flow and myocardial oxygen consumption; and4) inotropic interventions (isoproterenol, calcium, norepinephrine) as well as coronary dilatation (dipyridamole) may considerably augment 201T1 uptake in accordance with changes in myocardial oxygen consumption and/or myocardial flow.It is concluded that myocardial 201T1 uptake is determined by multiple factors. The major determinants have been shown to include (i) muscle mass, (ii) myocardial flow and (iii) myocardial oxygen consumption. The clinical data obtained from patient groups with normal ventricular function, with coronary artery disease, with left ventricular wall motion abnormalities and with different degree of left ventricular hypertrophy are correlated with quantitated myocardial 201T1 uptake.

Download Full-text