摘要:

It has been shown that cineangiographic measurement of the mean rate of circumferential fiber shortening (mean VCF) at the minor left ventricular equator is a reliable method for evaluating the mechanics of cardiac performance. Since fiber shortening can be derived from the echocardiogram, we sought to validate the measurement of mean VCFby this noninvasive technic in patients studied by both methods. In 15 patients considered to have normal left ventricular function, the average mean VCFdetermined by ultrasound was 1.29 ± 0.23 circumferences/sec, while in the 13 patients with reduced left ventricular performance this value was 0.75 ± 0.16 circumferences/sec (P< 0.001). Values of mean VCFby the two technics were similar and separated normal from abnormal ventricular function in 27 of 28 patients. The average mean velocity of posterior wall motion was 4.7 ± 1.1 cm/sec in normal patients and 3.9 ± 1.3 cm/sec in abnormals, but posterior wall velocities did not correlate well with either ultrasound or cineangiographic determinations of mean VCF. Ejection fraction calculated from ultrasound measurements correlated significantly with the ejection fraction calculated by cineangiography (r = 0.83,P< 0.0001). The ejection fraction and mean VCF, as determined by ultrasound in the 28 patients, correlated well (r = 0.92,P< 0.0001), but there were six discordant points.From these studies we conclude that the ultrasound determination of mean VCFis a valid method for distinguishing normal from abnormal myocardial performance of the left ventricle. These data also support the use of ultrasound in determining ejection fraction. Estimation of posterior wall velocity, although perhaps useful in the serial study of the same patient, seems limited in its ability to assess cardiac performance accurately.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

It may be difficult to evaluate sinus bradycardia in the elderly since sinus rates below 50 beats/min may occur normally with aging. Seven asymptomatic bradycardic subjects (heart rates 41-51 beats/min), ages 67-79 years, with no evidence of impaired cardiac performance and taking no drugs, were compared with four age-matched controls (heart rates 60-84 beats/min). Autonomic function was tested with the Valsalva maneuver, amyl nitrite inhalation, methoxamine infusion, head-up tilt, and atropine intravenously (2 mg).Cardiac index at rest was normal in bradycardic subjects (2.4 ± 0.1 SEM); increased cardiac stroke volume (SV) compensated for the slow heart rate. With supine bicycle exercise, increase in cardiac output per 100 ml increase in oxygen consumption was normal in bradycardics (885 ± 60 ml compared to 907 ± 171 ml in controls). This exercise response was achieved mainly by increased SV in bradycardics and by increased heart rate in controls. Significant increases in cardiac output occurred with both atropine and atrial pacing in bradycardics, but not in controls. Autonomic impairment was not found. Increased vagal tone in bradycardics was suggested by a lesser heart rate response to exercise and passive tilting.Hence, a heart rate below 50 beats/min in elderly people does not necessarily indicate depressed cardiac performance. Further evaluation of the significance of bradycardia in these subjects requires long-term observation.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Four cases with transient electrocardiographic features which have been attributed to left posterior hemiblock (LPH) are reported. These features were induced by the exercise test in patients with severe coronary artery disease. In all of them the following exercise-induced changes were noted: (1) A shift of the main QRS forces inferiorly and to the right (between +90° and +120°). (2) A definite shift of the initial 0.02 QRS vectors superiorly and to the left, causing a small Q wave to appear in leads II, III, and aVFand/or to disappear from leads I and aVL. (3) A SIQIIIpattern. (4) A leftward displacement of the precordial transition zone. (5) An increase of QRS duration in about 0.02 sec. Gradual disappearance of the exercise-induced axis shift was observed in all four cases and these findings were compatible with multiple degrees of “incomplete’ LPH. The occurrence of transient LPH patterns was related to the development of acute, transient injury in the posteroinferior wall of the left ventricle in the presence of segmental or widespread coronary artery disease and chronic posteroinferior damage. Before the exercise test, two patients had electrocardiographic patterns suggesting old myocardial infarction and the other two had repolarization changes related to inferior myocardial ischemia according to the angiographic findings.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Among 142 cases of bacterial endocarditis (BE), complete heart block (CHB) was found in six cases (4%) and first-degree (1°) or second-degree (2°) A-V block in 14 cases (10%).The aortic valve was involved in 18 of 20 cases with atrioventricular (A-V) conduction disturbance, including all six cases of CHB.Anatomic observations (four autopsy, one operative) were made in five of the six cases of CHB. In these cases, a common finding, in addition to involvement of the aortic valve, was extension of the infection to adjacent structures resulting in cardioaortic fistulae. CHB likely resulted from extension of infection to the major conduction tissues.Five of the six patients with CHB died suddenly while in the hospital. One patient was treated with electric pacing while the infection was being controlled and, 38 days later, underwent successful replacement of the aortic valve. Conduction abnormalities are important possible complications of aortic valvular BE. Prompt pacing may be a lifesaving procedure, allowing eradication of infection as a prelude to surgical therapy.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Measurements of human femoral arterial wall properties have been obtained transcutaneously in a group of males who were clinically free of arteriosclerosis obliterans. The patients were divided into three groups according to age: under 35, 35-60, and over 60 years. Diameter and changes in diameter were measured using an ultrasonic echo-tracking system. Arterial pulse pressure was determined by the auscultatory method. The results suggest that arteries become stiffer with age. The pressure-strain elastic modulus (Ep) varied from 2.6 ± 0.3 SEM × 106dynes/cm2in the young group to 6.3 ± 1.0 SEM × 106dynes/cm2in the old group. These values are similar to those reported by other investigators using invasive and in vitro technics. Although statistical comparisons indicate a significant difference between groups, there was considerable variation within the groups. Not infrequently, values for Ep obtained from individuals in the oldest group fell well within the range of the values obtained in the young group.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Electrocardiograms were recorded during and at 2-min intervals following maximal treadmill exercise in 100 patients and were correlated with coronary arteriograms, left ventricular cineangiograms, and resting and exercise cardiac hemodynamics. The incidence and extent of exercise-induced “ischemic’ S-T segment depression increased significantly (P< 0.01) with increasing extent of coronary artery disease (CAD). A criterion of abnormality of 1.0 mm or greater S-T depression most accurately predicted the presence of CAD with a specificity (true negative) of 89% and a sensitivity (true positive) of 62%. Criteria of ≧0.75 and ≧0.5 mm S-T depression offered improved sensitivities (68 and 84%, respectively) but markedly reduced specificities (78 and 57%, respectively).A significant correlation (P< 0.005) was found between increasing extent of exercise-induced S-T segment depression and the pulmonary artery wedge pressure during exercise. There were no correlations between the presence or extent of exercise-induced S-T depression and the resting or exercise pulmonary artery pressure, cardiac index, stroke-volume index, or exercise factor, or the resting left ventricular dp/dt, left ventricular end-diastolic pressure, left ventricular ejection fraction, or presence of asynergy on the left ventricular cineangiogram.The maximal treadmill exercise test provided a noninvasive method for predicting the presence and extent of significant CAD in the individual patient with chest pain. Although a normal treadmill exercise test provided little insight into the underlying resting and exercise hemodynamics, an abnormal treadmill test (≧1.0 mm S-T depression) was associated with an abnormal increase in left ventricular filling pressure with exercise in 90% of the patients.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Myocardial perfusion scintigraphy was performed in 30 intact anesthetized dogs following intracoronary injection of99mTc-labeled human albumin microspheres (HAM). The normal dog myocardial image pattern was established. This technic detected myocardial infarcts resulting from small vessel occlusions and flush coronary branch occlusions when the coronary angiogram appeared normal. Myocardial infarcts as small as 1½ cm were seen. Toxicologic studies in 47 dogs failed to demonstrate significant changes in blood pressure, heart rate, electrocardiogram, or serum CPK activity following intracoronary injections of HAM in doses up to 200 times that required for adequate myocardial scintigraphy. Gross and microscopic examination of hearts 1-6 weeks after HAM injection showed minor abnormalities also seen in matched controls receiving coronary arteriography alone. Preliminary results in 33 patients substantiate the safety of this technic. Human myocardial scintigrams reported here reveal anatomic detail not previously demonstrated by other external imaging methods.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The present paper reports the results of angiotensin infusion in 11 patients with severe atherosclerosis of the lower limbs adding a brief discussion of indications with inherent dangers and contraindications.The study confirms the results of Dahn et al.4,5that pharmacologically induced hypertension may increase distal perfusion pressure and flow and relieve resting pains. It is our opinion, however, that only a very limited number of patients presenting with severe foot ischemia and resting pains can profit from this treatment because of frequent contraindications such as coexistent hypertension and coronary heart disease.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Tritiated digoxin turnover studies were performed in nine children aged 4 days to 7 years. Mean serum turnover time was 32.5 (range 18-48) hours, and the 3-day urine and stool excretion was 55% of the total dose administered. These findings are quite similar to those observed in adults and indicate that the larger doses of digoxin required for digitalization in infants are not accompanied by increased metabolism or excretion but by increased blood levels and presumably increased tissue concentrations of the glycoside.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Symptoms and electrocardiographic changes of acute myocardial ischemia in a 10-year-old boy resulted from congenital atresia of the ostium of the left coronary artery. At 14 years of age persistence of symptoms and a positive exercise test prompted surgical treatment by aortocoronary artery saphenous vein bypass graft. Two months postoperatively, the symptoms and the abnormal findings on exercise test had subsided and forward flow through the graft to the left coronary artery was demonstrated by contrast angiography.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID