ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08794.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACT.Hypoxia and ischaemia produce relaxation of the vascular smooth muscle of the resistance vessels in the myocardium. A low pH may contribute to the arteriolar dilatation but cannot account for the major response. In all likelihood the reduced pO2acts indirectly by release of a vasodilator mediator rather than by a direct effect on the vascular muscle. Potassium release may account for a transient component of the vasodilation, but it appears that a major factor is the release of adenosine from the ischaemic tissue. Adenosine also appears to be responsible for slowing of the sinus rate and impaired A‐V conduction in myocardial ischaemia. These observations are of clinical significance because hypoxia‐induced A‐V block, such as may occur in inferior myocardial infarction, can be abolished by an adenosine antagonist such as aminophylline. In contrast, adenosine is also useful in the treatment of some cardiac arrhythmias. Supraventricular tachycardia, in which the A‐V node is involved in the re‐entrant pathway, is readily abolished in humans by the intravenous administration of small doses of

ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08795.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACT.This paper discusses three specific aspects of coronary circulation as they relate to the patient with coronary artery disease. Firstly, the normal autoregulatory and metabolic control of the coronary circulation is considered in the light of current understanding of the relevant processes. Secondly, the implications of microcirculatory heterogeneities are discussed. Thirdly, the implications of the current debate on the impact of cardiac contraction for our understanding of the perfusion of the myocardium in compromised circumstances are analysed in an attempt to provide the clinician with a tool for assessing current therapy.

ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08796.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08797.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACT.Under certain conditions, a progressive increase in vascular resistance occurs within ischaemic myocardium during the first three hours after coronary artery stenosis. Measurements of vasodilator reserve in the ischaemic region demonstrated that this is at least partly due to an increase in vascular smooth muscle tone. Two hypotheses were suggested as an explanation: release of vasoconstrictors within the ischaemic area, or a decreasing release of vasodilators. Potential coronary constrictors considered included norepinephrine, PGF2α, thromboxane A2, and high K+. Each of these substances was eliminated as the source of the vasoconstriction by pharmacological studies on ischaemic canine hearts. Measurement of adenosine release from isolated guinea pig hearts provided support for the possibility that the vasoconstriction results from a decreasing release of metabolic vasodilatators. Throughout the period of ischaemia, both blood flow and myocardial function were far below the levels that could have been achieved in the presence of the stenosis. We conclude that during moderate ischaemia, myocardial function and blood flow are linked in a positive feedback cycle which promotes reduced ventricular function and coronary blood flow

ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08798.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08799.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08800.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACT.Patients with chest pain syndromes and normal coronary angiograms were studied with a new set of methods that included thermodilution coronary sinus blood flow and coronary dye dilution curves with special computer analysis, oxygen and lactate determinations, thallium scannings, atrial pacing and dipyridamole tests.The following observations and conclusions were made:1Patients with cardiac hypertrophy have a reduced circulating coronary blood volume in relation to the left ventricular mass; this may play a role in patients' vulnerability to ischaemia.2During pacing‐induced angina a significant imbalance between oxygen supply and demand can be demonstrated in patients with »syndrome X».3Dipyridamole‐induced chest pain as a result of myocardial ischaemia seems to occur in patients with normal coronary arteries.4Marked ischaemia evidenced by a regional intensity reduction of 25% or more in thallium scans results in a significant increase in coronary volume. This is obviously due to mobilization of reserve vasculature as a response to ischaemia. A reduction in the ratio of myocardial oxygen supply to demand was demonstrated even in connection with milder defects, the regional intensity reduction being as low as

ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08801.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACT.For many years the paradigm of coronary atherosclerosis, set by pathologists, was the far‐advanced lesion containing extensive atheromatosis with calcifications. From the point of view of understanding atherogenesis, however, it is much more rewarding to study the coronary artery in patients without clinical evidence of obstructive coronary artery disease. In fact, the normal coronary artery is most revealing in showing discrete intimal changes, which consist of a splitting of the internal elastic lamina accompanied by a proliferation of vascular smooth muscle cells. This process eventually results in the formation of the musculo‐elastic layer. In time the cellular and muscular appearance of this layer gradually transforms into a more densely packed fibrous texture. It is of interest, from a point of view of atherogenesis, that the early atherosclerotic lesions often display the histologic features of the musculo‐elastic layer at the base of the plaque. Hence, these observations support the concept that the basic lesion in coronary atherosclerosis is a proliferation of vascular smooth muscle cells, most likely as a response to injury. To this extent a dysfunction of the endothelial cell barrier may by crucial.The observations also indicate that the mechanisms involved in atherogenesis also may alter vascular tone and hence, may contribute to a »spasmic state» of the coronary arteries. A classification of angina pectoris, on the basis of pathogenesis into organic and spasmic may thus prove to be sim

ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08802.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACT.The degree of narrowing of coronary artery that caused angina pectoris, was estimated in female and male patients with single vessel coronary artery disease, with the aid of quantitative measurements of a single stenosis in arteriograms. In female patients, the onset of mild angina pectoris (NYHA, functional class I‐II) occured when the coronary artery diameter was reduced by an average of 41 per cent, whereas it could not be estimated reliably in male patients because they nearly all had well developed collaterals bypassing the stenosis. For severe angina pectoris (NYHA, functional class III‐IV) the mean stenosis was 72 per cent in female and 78 per cent in male patie

ISSN:0001-6101    

DOI:10.1111/j.0954-6820.1985.tb08803.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY