摘要:

Indirect systolic time intervals (STI) corrected for heart rate were compared at rest and immediately following 3 minutes of moderate supine exercise in 33 normal subjects and 32 age- and sex-matched patients with coronary artery disease (CAD). The intervals were correlated with measurements of cardiac index (CI), stroke volume index (SVI), mean pulmonary artery and wedge pressures obtained under identical conditions of rest and exercise, and with resting left ventricular end-diastolic pressure (LVEDP), LV dp/dt, exercise factor, ejection fraction (EF), and extent of CAD.Total electromechanical systole (Q-A2c) was the same at rest in both normal and CAD groups and did not change with exercise in either group. The CAD group had a significantly longer preejection period PEPc), shorter left ventricular ejection time (LVETc), and larger PEP/LVET at rest and exercise than the normal group. Both groups responded to exercise with a significant reduction of PEPc, prolongation of LVETc, and reduction of PEP/LVET. Significant correlations were found between these STI and SVI, CI, LV dp/dt, LVEDP, and EF, which explained the differences in STI between the normal and CAD groups. However, exercise did not improve the sensitivities of the STI in detecting disordered hemodynamics in the patients with CAD. Furthermore, the STI failed to predict reliably hemodynamic abnormalities in the individual patient which were not already clinically obvious.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Echocardiographic measurements of minor axis and wall thickness and calculations from these two measurements of left ventricular end-diastolic volume and mass were performed in 24 patients and compared with angiocardiographic measurements of the same variables in corresponding patients. The echo-measured left ventricular end-diastolic chamber dimension (Dd) correlated closely with the angiographic minor axis in the AP plane (correlation coefficient 0.87 and SE ± 0.45 cm) and with the minor axis from the lateral film (r = 0.91, SE ±0.39 cm). Similar correlations were found between measurements by these methods of wall thickness (r = 0.89, SE ±1.3 mm), of end-diastolic volume (r = 0.94, SE ±30.6 cc), and of left ventricular mass (r = 0.88, SE ±49.19 g). The reproducibility of this method was established by independent recordings and measurements of echo Polaroid films by two observers. The percent systolic wall thickening, as determined by echocardiography, identified subjects with ejection fractions greater or less than 0.50. Echocardiography offers a reliable and reproducible method for measuring left ventricular wall thickness and mass. Finally, ultrasound may provide an accurate method for measuring systolic wall thickening in man.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Four patients are described with different degrees of conduction disturbance within the His bundle. In one patient with a Mobitz type II atrioventricular (A-V) block with normal QRS complexes the blocked atrial beats were followed by a His potential. Since the QRS complexes of the conducted beats were completely normal, the site of the block was thought to be in the distal part of the His bundle. In the other three patients with a 2:1 A-V block, a nearly complete A-V block, and a complete A-V block, two distinct His potentials could be discerned, one (H) following each atrial beat, the other (H′) preceding each ventricular activation. In the patient with 2:1 A-V block a Wenckebach phenomenon within the His bundle could be produced at certain atrial driving rates. Impulse conduction through the A-V node was normal in all four cases, as could be concluded from the effect of increased atrial driving rate and of accurately timed atrial premature beats. The site of the block could not be predicted from the conventional electrocardiogram.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

In order to answer the question whether the atrium is a link in the pathway of ventricular reciprocation or whether the A-V node itself is the reflection point of the echo, a special stimulation program was followed in six patients in whom ventricular echo beats with stable time relations could be elicited by regular pacing of the right ventricle or by the application of appropriately timed right ventricular premature beats during regular pacing of the right ventricle. In these experiments the atrial septum was stimulated earlier than the expected arrival at the atrium of the retrograde impulse in the course of the echo sequence. The influence of stepwise (steps of 5 msec) advancing of this atrial “preexcitation” on the timing of the ventricular echo beat was studied.We found that the atrial septum could be preexcited without interfering with the ventricular echo beat time relations over a time interval less than 5 msec in one patient, less than 10 msec in one, less than 20 msec in two, and less than 30 msec in two cases. When the time interval needed for the stimulated atrial impulse to reach the atrionodal margin is taken into account, it seems likely that the atrium participated in the echo pathway in the four cases with minimal atrial preexcitation intervals of 20 msec or less, and that in the two cases with a minimal atrial preexcitation interval of 30 msec the echo reflection point was localized in the upper part of the A-V node.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

This study of individuals with familial and sporadically occurring 46 XX or XY Turner phenotype documented a wide range of right- and left-sided cardiovascular abnormalities and a previously unreported eccentric hypertrophy of the left ventricle.A mother and five of her seven children had abnormal cardiovascular findings. Five had an abnormal electrocardiogram with frontal ÂQRS of −60° to ±180° and rS or rsr′ in V1and rS, qrS, or qRS in V5. Catheterization demonstrated the following anomalies: coarctation of the aorta in three, valvular aortic stenosis in one, pulmonary valvular insufficiency with atrial septal defect in one, and pulmonary arterial branch stenosis in one child. All six had a similar abnormality of the left ventricle on angiocardiography. During systole and also in diastole the cavity was encroached on in its superolateral and posteroinferior aspects. Septal hypertrophy altered right ventricular contour in two.A similarly abnormal electrocardiogram and left ventricle were found in four unrelated individuals with the XX, XY Turner phenotype. Three had pulmonary stenosis; in two there was an associated septal defect. The fourth, with no associated cardiac defect, died in heart failure at 5 months of age. At necropsy she had marked eccentric biventricular hypertrophy, chiefly involving the left ventricle so that the chamber was reduced to a slitlike cavity. The hypertrophied septum bulged into the right ventricular outflow tract.A number of cardiovascular anomalies occur in familial and sporadic instances of this syndrome; eccentric ventricular hypertrophy recognizable by an electrocardiographic abnormality seems to be a distinctive cardiac lesion in the XX, XY Turner phenotype. Except for the unusual and, we believe, characteristic ECG, there was no clinical clue on physical examination or cardiac series of chest roentgenograms to suggest the presence of eccentric left ventricular hypertrophy. We recommend that selective left ventricular angiocardiography be performed when patients with the Turner phenotype undergo diagnostic cardiac catheterization, especially when the frontal ÂQRS is superiorly directed.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Reported is the first surgically corrected case of tetralogy of Fallot with anomalous origin of the left pulmonary artery from the ascending aorta. The diagnosis of origin of the left pulmonary artery from the aorta depends on an aortogram, but clinical hints are increased vascularity in the left lung compared with the right lung and a continuous murmur. In tetralogy of Fallot, when there is late filling of the left pulmonary artery after a right ventricular cineangiogram, anomalous origin of the left pulmonary artery should be suspected and confirmed by an aortogram. Differentiation from complete absence of the left pulmonary artery, which is also often associated with tetralogy of Fallot, is possible by chest roentgenogram.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Over a 3-year period of observation, the electrocardiogram in an adult patient with an ostium primum atrial septal defect changed from first-degree atrioventricular block alone to right bundle-branch block and left-axis deviation (left anterior hemiblock) with variable atrioventricular block. Coronary atherosclerosis was excluded by selective coronary arteriography. Although right bundle-branch block and left anterior hemiblock are commonly present at birth in patients with endocardial cushion defect, this is believed to represent the first reported instance in which these electrocardiographic abnormalities have developed under observation in later life. It is postulated that chronic hemodynamic stress contributed to the progression of disease in the conduction system.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Premature closure of an atrioventricular valve was observed in 80 of a group of 519 subjects catheterized for aortic insufficiency (AI) or mitral insufficiency (MI), or both. Sole premature mitral closure (PMC) was present in nine subjects, sole premature tricuspid closure (PTC) in 40, and combined PMC and PTC in 31. Clinically PMC was associated with a first sound that was soft or absent in 75% and an atrial contraction sound in 50% of the subjects with dominant aortic insufficiency. PMC or PTC, or both, were verified at surgery in three subjects and were produced experimentally in intact dogs by acute AI. The presence of PMC and PTC appears related to the severity and chronicity of valvular disease.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Absence of the atrioventricular septum and a cleft in the anterior leaflet of the mitral valve is characteristic of almost all anomalies resulting from maldevelopment of the endocardial cushions. These changes produce a specific angiocardiographic picture, characterized in systole by a scalloped right border of the left ventricular outflow tract, with a small lucent notch within it, and in diastole by a gooseneck appearance of the subaortic portion of the ventricle. This appearance is independent of the associated hemodynamic changes or the presence of other lesions. Because the angiocardiogram provides a direct demonstration of the underlying anatomic abnormalities, it is the most sensitive diagnostic method for the recognition of an endocardial cushion defect.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Tachyarrhythmias occur in about one third of patients with acute myocardial infarction (MI), and may precipitate serious consequences when they arise. Mechanisms of arrhythmogenesis in MI are imperfectly understood, but five categories of factors contributing to ectopic tachycardias are discussed. These include metabolic, anatomic, autonomic, hemodynamic, and iatrogenic causes. Each of the atrial, junctional, and ventricular tachyarrhythmias is briefly considered, and therapy is outlined.Prevention of tachyarrhythmias and prompt treatment when they occur have substantially reduced mortality in acute MI, and constitute a primary objective of coronary care. However, better understanding of mechanisms of arrhythmogenesis, better systems of automated monitoring, and better modes of therapy, especially antiarrhythmic drugs, are urgently needed.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID