ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID

摘要:

Case histories of two infants with anomalous origin of the left coronary artery from the pulmonary artery are presented.Both infants underwent ligation of the left coronary artery at its entrance into the pulmonary artery. One survived the operation and is asymptomatic 3 years postoperatively, whereas the second one died at surgery.A classification of instances of anomalous left coronary artery according to adequacy of the collateral circulation between the left and right coronary systems is proposed.Surgical ligation of the pulmonary artery orifice of the left coronary artery is indicated only if the presence of a left-to-right shunt into the pulmonary artery is demonstrated.If the direction of blood flow is from pulmonary artery to left coronary artery, surgical procedures should be aimed toward increasing either pulmonary artery oxygen content or left coronary artery perfusion pressure.

ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID

摘要:

The clinical features and follow-up data on107 patients who had a clinical diagnosis of aneurysm of the thoracic aorta made at the Mayo Clinic in the period 1945 through 1955 were reviewed. The ratio of male to female was 2.8 to 1, and the average age at the time of diagnosis was 59.3 years. Fusiform aneurysms were four times as frequent as saccular aneurysms; the most common location of the former was the descending thoracic aorta and of the latter the ascending thoracic aorta. Most of the aneurysms (73 per cent) were probably arteriosclerotic in origin. Symptoms, usually pain, and physical signs were present in a minority of patients and indicated a large aneurysm with a poor prognosis.Diastolic hypertension was present in almost half of the patients at the time of diagnosis and had an adverse effect on the patient's survival. Associated arteriosclerotic cardiovascular disease was present in 40 (37 per cent) of the patients at the time of diagnosis; some of these patients had multiple associatedcardiovascular lesions. The presence of associated coronary, cerebral, or other peripheral arterial occlusive or aneurysmal disease had the most deleterious effect on survival. The prognosis for patients with large aneurysms was poorer than for those with small aneurysms.Information as to the cause of death was available in 59 (83 per cent) of the 71 patients known to be dead at the time of follow-up. Approximately a third of the deaths were due to rupture of the thoracic aortic aneurysm, and approximately a half, to associated cardiovascular disease, particularly that due to arteriosclerosis.It is believed that this study of patients with untreated aneurysms of the thoracic aorta may be used as a guide to the selection of patients with aneurysm for surgical treatment and may serve as a basis for evaluating the long-term results of such treatment.

ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID

摘要:

The Chardack-Greatbatch implantable pacemaker has proved a worthwhile device for the management of both congenital and acquired heart block. The procedure used for implantation in 38 patients is described. The most frequent indication for use of the pacemaker is syncope due to heart block. Progressivecardiac enlargement was also an indication for pacemaker implantation in two of four children with congenital heart block. The pacemaker has also been useful in the management of surgically induced heart block and coexisting heart block that accompanies intracardiac lesions, such as aortic stenosis, which require open-heart surgery.Pacemaker failure due to electrode breakage occurred in two patients. In both instances, a replacement unit was successfully used. Three of the 38 patients have subsequently died from causes unrelated to pacemaking while one death resulted from pacemaker failure 12 months after implantation. The remaining 34 patients have remained free from cardiac symptoms during observation periods of 2 to 24 months.

ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID

摘要:

The effects on ventricular dimensions of intact, unanesthetized patients of isoproterenol, a drug that stimulates beta adrenergic receptors, and of methoxamine, an agent that stimulates alpha adrenergic receptors, were studied by means of a cineradiographic technic. The administration of isoproterenol to 13 patients consistently resulted in a decline in the end-systolic dimensions of both ventricles. A smaller and less consistent decrease in ventricular end-diastolic dimensions was noted. In contrast, the administration of methoxamine resulted in an increase of ventricular end-diastolic dimensions in all 10 patients studied. Left ventricular end-systolic dimensions increased during methoxamine infusion in the eight patients in whom the measurements were made, but changes in right ventricular end-systolic dimensions were inconsistent. The alterations in heart rate induced by isoproterenol and methoxamine could account only in part for the observed changes in ventricular dimensions. It is anticipated that the experimental approach used in this study, that is, the measurement of ventricular dimensions in intact, unanesthetized human subjects, will help to provide a more complete analysis of the action of drugs on the circulation of man.

ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID

摘要:

The myocardial clearance of potassium may be obtained by precordial counting after a single intravenous injection of K42Cl or Rb86Cl. The theoretical foundations of the method and the technic developed have been presented and discussed.The distribution of the values obtained in normal subjects and in subjects with coronary insufficiency is in agreement with the clinical expectancy, and changes of the observed MCK after nitroglycerin agree with the results obtained by other investigators who measured coronary blood flow by the indirect Fick method.In agreement with the observations of other investigators in rats and dogs, the amount of K42or Rb86in the myocardium was found to change very little for an appreciable time interval after the first circulation, despite the significant recirculation and the decreasing arterial concentration. This observation and the fact that MCK values in normal subjects closely agree with the accepted values for coronary blood flow confirm Sapirstein's findings in rats and dogs, and support the view that the organ uptake of Rb86or K42immediately after single intravenous injection reflects the fractional organ blood flow.As obtained with the present technic, and similarly with the indirect Fick method, MCK reflects the flow per gram of myocardium and not the total coronary blood flow. MCK, however, has the advantage that every unit volume of myocardium, no matter how well it is perfused or through which vessels it is drained, contributes to the precordial counting rate in variable proportions determined by the efficiency of the counting method.

ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID

摘要:

Various technics for recording the electrocardiogram while the patient was exercising on the Master two-step apparatus were evaluated. Satisfactory tracings were obtained both by radiotelemetry (when the apparatus was properly aligned) and a direct hook-up technic that requires only standard equipment. Recommended electrodes are described, electrode positions discussed, and possible pitfalls of the technics enumerated. It is concluded that for the specific purpose of monitoring the two-step test, radiotelemetry is unnecessary and perhaps less desirable than direct hook-up monitoring.

ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID

摘要:

Experiments were done to see if reserpine, in small oral doses, alters the responses to tyramine and norepinephrine in man. Each of seven normotensive subjects was studied on three occasions. The first and third sessions served as pre- and post-treatment control sessions; the second session was held after oral administration of reserpine (0.25 to 1 mg. per day) for 2 weeks. Blood pressure was measured with a sphygmomanometer, and forearm blood flow was measured with a water plethysmograph. Reserpine reduced resting blood pressure and heart rate but forearm bloodflow did not change. The pressor, forearm vasoconstrictor, and bradycrotic actions of intravenous tyramine were suppressed by reserpine, but the pressor, vasoconstrictor, and bradycrotic actions of three intravenous doses of norepinephrine were not augmented significantly. The results indicate that oral administration of small doses of reserpine may cause depletion of endogenous catecholamines in man as suggested by the suppressed response to tyramine. The decreased response to tyramine was not accompanied by hypersensitivity to exogenous norepinephrine. In equipressor doses norepinephrine produced greater forearm vasoconstriction and more reflex bradycardia than did tyramine.

ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID

摘要:

In this study the range and upper limits of seven QRS-voltage criteria for left ventricular hypertrophy have been established in healthy, fit male young and middle-aged populations. The upper limits of normal for younger and older populations differ considerably. Agreement with the published literature occurred with some of the criteria in the older age group.

ISSN:0009-7322    

出版商:OVID    

年代:1964

数据来源: OVID