ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

In a patient with atrial septal defect and incomplete right bundle-branch block atrial echo beats were observed after atrial premature beats, induced with a gradually decreasing delay during regular driving of the atrium. The time relations of these atrial echo beats could be accurately defined. Considerable prolongation of the atrioventricular (A-V) conduction of the premature atrial response was found to be a necessary condition for the occurrence of atrial reciprocation, which was restricted to small and very circumscript delay ranges.Three types of atrial echo responses could be discerned. The concept of a dual A-V conduction system was not sufficient to explain the genesis of these three types. The assumption of a third pathway in the upper part of the A-V node was needed. Arguments in favor of a longitudinal dissociation of one of the two pathways postulated in the concept of dual A-V transmission were given.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

A new method for the measurement of cardiac output has been tested in 69 patients undergoing catheterization of the right and left sides of the heart. It is based on the recently described fiberoptic hemoreflection method. In order to verify the validity of these measurements, correlations with stroke indices determined by the Fick principle and by biplane angiocardiography were also carried out. Details of the biplane angiocardiographic technique and of the fiberoptic calibration methods are given.Comparisons were carried out in 37 instances between the results after injections in the pulmonary artery (mean stroke index, 40.8 ml/m2) and in the left ventricle (mean, 42.9 ml/m2). Good agreement was found, r=0.930, with a mean difference of 2.1 ml/m2.Stroke indices by fiberoptics (FO) were first compared with those obtained by the standard Fick method. In 100 determinations the mean stroke index by FO was 45.7 ml/m2, and Fick 49.0 ml/m2(r=0.859; confidence limits, 0.77<p<0.93). Correlations were then carried out in 42 instances between stroke index by FO (mean, 49.1 ml/m2) and by angiocardiography (mean, 48.2 ml/m2, r=0.799; confidence limits, 0.65<p<0.90). Various factors influencing the angiocardiographic method for determining stroke index are discussed.It is concluded, that the fiberoptic-indicator dilution method is an accurate system to determine cardiac output regardless of the site of injection (LV or PA). Its versatility, the lack of need for blood withdrawal, and the generally satisfactory agreement with angiocardiographic or standard Fick method recommend its general application when cardiac output determinations are required during the process of cardiac catheterization, provided sampling is carried out in the aorta.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

The hemodynamic effects of hypovolemia and acidosis were studied in 23 patients with cholera. Studies were made before and during fluid replacement and administration of alkali.The major hemodynamic abnormalities encountered before rehydration can be ascribed to a reduction in circulating blood volume. Hypovolemia was associated with a reduction in cardiac output, blood pressures, and central blood volume. Restoration of blood volume returned these variables toward normal.The chief effect of acidosis appeared to be a redistribution of blood from the peripheral to the central circulation; consequently, central blood volume, lesser circulation pressures, and cardiac output were relatively well maintained despite hypovolemia. Fluid administration without correction of acidosis favored a disproportionate increase in central blood volume, while reduction in hydrogen ion concentration attending fluid replacement resulted in a more even distribution of the circulating blood volume and reduced the possibility of engorgement of the pulmonary bed.It is postulated that this redistribution of blood stems from peripheral venoconstriction and a reduction in the capacity of venous reservoirs induced by acidosis.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Response to angiotensin infusion was evaluated in 11 normal children and 24 patients with suspected left ventricular dysfunction. This included 12 patients with endocardial fibroelastosis, three with idiopathic myocardial hypertrophy, one with cardiac glycogenosis, and eight with the Hunter-Hurler syndrome. In 20 of these 24 patients, cardiac catheterization findings confirmed the clinical suspicion of decreased left ventricular function. In 11 instances left ventricular dysfunction was diagnosed by an elevation of resting left ventricular end-diastolic pressure. In eight instances this was ascertained by a decrease in resting left ventricular stroke work when compared to the expected range, derived by using a linear regression formula based on 24 normal subjects. In only four instances were both abnormal; that is, the resting left ventricular stroke work was decreased and the left ventricular end-diastolic pressure was increased. In five of these 20 patients, abnormal left ventricular function was elicited only on infusion of angiotensin. Thus this test is a significant adjunct in our ability to determine myocardial malfunction at cardiac catheterization.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

The effects of long-term reserpine therapy (1) on cardiac output during rest and induced atrial tachycardia and (2) on atrioventricular (A-V) conduction were examined in a group of eight men with previously untreated essential hypertension. The patients were studied before and after 20 to 205 days of reserpine therapy. All studies were performed in the cardiopulmonary laboratory with the patients supine. Heart rate was controlled with a transvenous pacing catheter and a battery-powered pacemaker. After therapy six of six patients had a fall in cardiac output with a statistically significant difference (P<0.001) between the means of paired pre-reserpine and reserpine cardiac outputs during both rest and paced tachycardia. At comparable heart rates, atrioventricular conduction increased in six of eight patients following reserpine, and a significant difference (P<0.05) was evident when the means of pooled paired pre-and post-reserpine A-V conductions were compared.This study indicates that therapeutically administered reserpine in a hypertensive population (1) may significantly lower cardiac output at rest with no further decrease during induced atrial tachycardia, and (2) may increase A-V conduction and enhance second degree heart block during induced atrial tachycardia.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

External scintillation scanning of intravenously administered131I-labeled macro-aggregates of human serum albumin (131I-MAA) was employed to evaluate the distribution of pulmonary arterial blood flow in 61 normal subjects and in 100 patients with various congenital cardiovascular malformations. Intra-aortic administration of131I-MAA demonstrated that blood flow through subclavian-pulmonary artery anastomoses is directed principally to the lung on the side of the anastomosis; the relative concentration of131I-MAA in each lung after intravenous injection provided an index of the patency of the anastomosis or of the development of pulmonary atresia or pulmonary hypertension. In contrast to the findings in patients with a patent subclavian-pulmonary shunt, scans obtained from patients with a patent ductus arteriosus did not reveal a separation of the systemic arterial and systemic venous inflows to the lungs. The patency of superior vena caval-right pulmonary arterial anastomosis could be assessed after injection of131I-MAA into an upper-extremity vein.Anomalies characterized by increased pulmonary blood flow or elevated pulmonary arterial pressures, or both, increased the ratio of pulmonary blood flow in the lung apices relative to that in the dependent lung zones. Anomalies characterized by elevated pulmonary venous pressure, such as cor triatriatum and mitral regurgitation, were readily detected by demonstrating both a decrease in blood flow to the lung bases as well as an increase to the apices. Thus, in patients with known pulmonary arterial hypertension (mean pressure, >30 mm Hg) the ratio of upper to lower zone blood flow was always significantly higher if the arterial hypertension was accompanied by venous hypertension. For this reason, lung scans facilitated the screening of patients with pulmonary arterial hypertension for surgically correctable lesions such as cor triatriatum and mitral stenosis.The method described is technically simple, without risk, easily applicable to large numbers of patients, and provides clinically important information concerning many forms of congenital heart disease.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

While considerable information concerning the hemodynamic and angiographic features of idiopathic hypertrophic subaortic stenosis (IHSS) is available, data concerning the natural history of the disease are limited. The clinical courses of 126 patients with hemodynamically documented IHSS, examined repeatedly for up to 12 years, were analyzed. The older patients tended to be more severely symptomatic. Although the course was extremely variable, the patients who were asymptomatic initially tended to remain so, while those who were more disabled generally deteriorated, died, or improved spontaneously. Bacterial endocarditis occurred in three patients. Ten patients died as a consequence of the natural history of IHSS; six of these deaths were unexpected. Sudden deaths occurred usually in patients with no or mild obstruction, and in patients with both the familial and sporadic forms of the disease. Atrial fibrillation was observed in 8% of the patients, and abnormalities of atrioventricular conduction, in 30%. Absence of voltage criteria for left ventricular hypertrophy occurred more frequently in asymptomatic patients, those with mild obstruction, and those with familial IHSS. Pulmonary hypertension occurred in one third of the patients, and was associated with considerable clinical disability. Obstruction to right ventricular outflow occurred in eight patients (15%), two of whom had no associated obstruction to left ventricular outflow.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

The movements of two ultrasound echo signals, believed to arise from the anterior mitral leaflet and from the mitral ring, were studied in 30 normal subjects and in 100 heart-catheterization patients. Fifty patients had proven mitral stenosis. The echo from the anterior mitral leaflet is shown to have a complex pattern of movement. This pattern is analyzed into the opening and closing movements of the leaflet, and the underlying movement transmitted from the mitral ring. In the normal condition, the characteristic feature of leaflet motion is a sharp closing movement that follows the initial opening in diastole. This sharp closing movement is not seen in the presence of mitral stenosis. It is believed that the demonstration of a sustained wide-open poisition of the leaflet in diastole has the same diagnostic significance as the finding of a persistent positive-pressure gradient across the valve. The value of this method in diagnosing the severity of the stenosis is discussed.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID