ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Among the wide variety of causes of angina pectoris, two major categories may be recognized: the anatomic, causing arterial obstruction, and the functional.The anatomic causes may be divided according to anatomic sites as follows: (1) the major coronary arterial trunks and their epicardial branches, (2) the coronary ostia at the aorta, and (3) the intramyocardial “small” arteries. The major coronary arteries are by far the most common sites for anatomic lesions. Atherosclerosis in its various anatomic manifestations is responsible for about 90% of the cases of angina. Commonly, hypertension and, less commonly, valvular disease are associated. The balance of cases of angina result from various states given below. Nonatheromatous diseases of the major coronary arteries include embolism, primary dissecting aneurysm of a coronary artery, arteritis, and anomalous communication of a coronary artery. Coronary ostial narrowing results from various diseases of the aorta including atherosclerosis, saccular and dissecting aneurysm, inflammation, and calcification of the aorta in relation to origin of a coronary artery. Lesions causing obstruction of the intramyocardial arteries are commonly part of systemic diseases such as hematologic, embolic, metabolic, and degenerative.Functional causes of angina pectoris include aortic valvular disease and functionally related conditions, thyroid disease, and pulmonary hypertension.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

In the majority of instances, the clinical diagnosis of angina pectoris can be made from the history alone. The chest discomfort is characteristically a sensation of deep pressure, is occasionally of burning quality, is found near the sternum, not sharply localized, and has a gradual buildup. Its duration is most often 2-10 min, but may be 30 sec to 30 min or more. Physical effort, emotional strain, large meals, nightmares, or sexual intercourse are common precipitating factors. Nitroglycerin tends to relieve the distress within 1-2 min, but the response is often difficult to evaluate, especially with angina of brief duration or with acute unstable rest angina. Physical examination of the anginal patient is often negative between attacks. During an attack of rest angina, the physical examination usually reveals increased systolic blood pressure and tachycardia. A fourth heart sound and a delayed apical systolic murmur may be found. Premature ventricular beats may develop.The resting electrocardiogram is normal in the majority of patients with angina pectoris. During the anginal attack, the electrocardiogram usually reveals an increase of the heart rate and ischemic flat or downsloping S-T-segment depressions of 0.08-sec duration or more. The exercise electrocardiogram is most useful when the stress is sufficient to increase the heart rate to 85 or 90% of the predicted maximum for the age of the patient. An abnormal exercise electrocardiogram is found in 80-90% of patients with angina when they are tested by the graded treadmill exercise test of Sheffield and Reeves, but in only 50-60% of those tested by the Master's exercise test.Varieties of angina pectoris which may differ from the foregoing include: Prinzmetal's variant angina, unstable angina (acute coronary insufficiency, crescendo angina), atypical angina, and angina with syncope.Angina pectoris must be distinguished from the discomfort of anxiety neurosis, hiatal hernia, cervical spine disease, gallbladder disease, Tietze's syndrome, and post-herpetic neuralgia.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Coronary artery disease and angina pectoris are frequently associated with disordered myocardial function which may cause abnormalities in precordial motion, heart sounds, and/or systolic time intervals. The pathophysiologic basis for these abnormalities has been studied by correlating them with more direct measurements of myocardial function. Large a waves on the apexcardiogram and atrial gallops are related to accentuated left ventricular a waves which reflect diminished left ventricular compliance. Uncoordinated left ventricular contraction (asynergy) may cause abnormal systolic motion which can sometimes be recorded on the apexcardiogram. Ventricular (early diastolic) gallops in coronary artery disease are usually associated with extensive obstructive lesions, left ventricular asynergy, and a low cardiac output. Transient paradoxic splitting of the second sound in angina pectoris has been reported though rarely documented by phono-cardiography. Mitral insufficiency due to papillary muscle dysfunction implies significant damage to the papillary muscles and the surrounding ventricular wall, usually by severe coronary artery disease. Systolic time intervals are a sensitive technic which may reflect diminished contractility (prolonged preejection period) or low stroke volume (shortened left ventricular ejection time) in patients with coronary artery disease. However, systolic time intervals are also sensitive to many other pharmacologic and hemodynamic influences, including changes in left ventricular preload and afterload which may result in misleading values. Therefore, as a technic for evaluating individual patients with coronary artery disease and angina pectoris, the role of systolic time intervals remains limited.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The results of stress testing in patients being assessed for coronary artery disease have led to conflicting claims and conclusions. It seems reasonably clear that stress testing is of considerable predictive value inepidemiologic studies;i.e., patients manifesting or developing a positive exercise test have a much higher probability of subsequently experiencing coronary events (angina pectoris, myocardial infarction, or coronary death) than those individuals with normal stress tests. Moreover, the risk seems to be related to the degree of S-T segment depression. In contrast, despite earlier claims regarding thediagnosticaccuracy with which single-load stress tests could predict the presence or absence of ischemic heart disease in individual patients, studies correlating the results of testing with the degree and extent of angiographically demonstrated coronary artery disease have not consistently shown either acceptable sensitivity or specificity. Although on theoretic grounds it would be anticipated that multistage stress tests would be superior to single-stage protocols, this has not been borne out in the few published studies in which the results are correlated with angiography. Thus, the available evidence suggests that there remain appreciable numbers of patients with documented coronary artery disease in whom no ECG abnormalities are detected despite relatively intense levels of exercise, and an appreciable number of patients with abnormal ECG responses but normal coronary arteries. Stresses other than exercise have been and are being utilized in the evaluation of patients with chest pain; however, no single test as yet offers the desired specificity and sensitivity.We conclude that, in patients with typical angina pectoris or with chest pain which clearly does not resemble angina pectoris, stress testing appears to be superfluous since it provides little additional information beyond that which may be obtained from the patient's history. It is in those patients presenting with atypical anginal syndromes that a reliable noninvasive test would be of great value. Currently available technics are neither sufficiently sensitive nor specific to satisfactorily aid in solving this problem.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The successful medical management of a patient with angina pectoris requires careful attention to many factors including omission of smoking, control of hypertension, and weight reduction for the obese person. Newer knowledge of the importance of the product of the systolic blood pressure and the pulse rate in determining the threshold of angina affords a more meaningful approach to therapy. Each individual must be educated regarding the factors that aggravate and precipitate his distress so that these can be minimized, or prophylactic nitrite therapy can be appropriately applied. Emotional stress is of equal importance to effort in the production of angina. The mainstay stay of treatment is nitroglycerin and sublingual nitrites combined with beta-blocking drugs. Each drug or combination must be properly readjusted for the individual to assure optimum benefit. Digitalis, diuretics, antiarrhythmic drugs, antihypertensive agents, and radioiodine may be useful in selected cases.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The first portion of this paper represents a critical analysis of methods used in the determination of coronary blood flow in man. Coronary flow in man can be measured with the use of diffusible gases such as nitrous oxide, a procedure based on the Fick principle. In the presence of inhomogeneous perfusion, the time of equilibrium with coronary vein blood is difficult to establish, contributing to possible errors in the use of this method.Procedures which utilize substances which actively enter the cell, such as84rubidium,86rubidium,42potassium, and24sodium, are also employed. Only when the blood-tissue permeability is great in comparison to blood flow, is the exchange between blood and tissue a flow-limited process and can be used as an estimate of the nutrient circulation. Since the technic is based on the assumption that there must be equality of integrated mixed venous and coronary sinus tracer concentration after injection until the measurements are complete, any inequality in the extraction ratio of the heart and the body may introduce an error. This is the case after acute myocardial infarction. The difficulties introduced by perfusion differential are even greater when washin and washout curves are obtained following the injection of133xenon into the coronary artery.Technics which determine flow by interpreting the slope of an exponential decay curve in the presence of underperfused areas must be interpreted with great caution in the presence of coronary artery disease. Measurements of total coronary sinus outflow by thermodilution or by indicator dilution suffer from possible inadequate mixing of blood with the injectate. They do not measure nutritional blood flow. The determination of phasic coronary flow with the ultrasonic Doppler flowmeter is promising, but the technic is invasive, and there are inherent difficulties in correct positioning of the catheter tip.Determination of regional coronary flow is now also in clinical use. Usually gamma-emitting diffusible tracers such as133xenon or43potassium are used in addition to a scintillating camera and computers for data acquisition. Regional flow can be calculated with clearance formulae. Like other procedures used in the measurement of coronary flow, these methods suffer from the disadvantage that it is difficult to relate the rate of disappearance of the tracer substance to the degree of homogeneity of perfusion.Subsequent portions of this report deal with changes in coronary flow in ischemic heart disease. As is to be expected, results are influenced by the technic used. This applies particularly to studies employing the xenon washout method. There is general agreement however that, in the presence of coronary artery disease, the coronary flow fails to respond adequately to coronary vasodilator drugs. An explanation may lie in the so-called “coronary steal”: a decrease in resistance at the precapillary level of nonoccluded vessels could result in a decrease in blood flow to muscle supplied by that artery. The importance of coronary collateral circulation was described, and the development of collaterals from preformed thin-walled blood vessels was discussed. It is unlikely that the development of extensive coronary collaterals can prevent angina pectoris. Basic principles underlying coronary microcirculation, as they affect the oxygen supply of the heart muscle, were stressed. New findings relating to this subject are countercurrent flow and asymmetric capillary arrangement. This provides favorable oxygen distribution to the heart muscle. Of importance also is the existence of recruitment of capillaries (perfusion of the increased number of capillaries as perfusion pressure rises).

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID