An improved method for determination of 4,4'-methylene bis-(2-chloroaniline) (MOCA) in urine.
Explore the source record for details and available documents.
Benzhydryl Compounds↗
Biomedical subjects
A L Klein
Publications and source records attributed to A L Klein.
Changes in leadership appraisal as a function of the stress of a simulated panic situation.
Research by Mintz and Kelley, Condry, Dahke, and Hill left unresolved the question of what level of personal threat leads to group incoordination of "panic behavior." The present study set out to resolve this issue and to explore the additional relationship between leadership and behavior in the panic situation. The dependent variables were Likert-type questionnaire items designed to investigate the level of responsibility attributed to a leader by members of a group as a function of four variables: (a) two levels of stress (threat of shock or of small monetary loss); (b) two levels of leadership authority (elected or appointed); (c) two conditions of leadership ("me-last" or "me-first"); and (d) group success or failure. The specific questions were adapted from earlier pilot work by Sulzer and Sisti. One hundred and forty-four males were run in this 2 X 2 X 2 X 2 factorial design with a nonfactorial control group. The task setting, which required subjects to retrieve their wooden cones through the same hole, was designed to be analogous to the kind of situation that would occur in a theater fire where only one narrow exit existed. The results support the contention of Kelley that group incoordination (panic) increases under personal threat. Additional results were: (a) Leaders facilitated achieving the goal of safe exit; (b) elected leaders were given more responsibility and were seen as more competent than appointed leaders, but only when the stress is comparatively low, as otherwise the difference in evaluation narrows and reverses; and (c) success or failure seems to have had little effect on the leader's evaluation by the group.
Adolescent↗
Transesophageal echocardiography-guided approach to cardioversion of atrial fibrillation.
In patients with atrial fibrillation, electrical cardioversion is often performed to relieve symptoms, to improve left ventricular function, and to decrease thromboembolic risks. However, cardioversion of atrial tachyarrhythmias is associated with an increased embolic risk, with an event rate of up to 5.6%. The American College of Chest Physicians recommend 3 weeks of systemic anticoagulation before elective cardioversion and 4 weeks of systemic anticoagulation afterwards. Expulsion of preexisting left atrial (LA) thrombi with resumption of sinus rhythm has traditionally been considered the mechanism for this increased embolic risk associated with cardioversion. The advent of transesophageal echocardiography (TEE) has allowed accurate detection of LA thrombus. Moreover, recent studies using TEE have identified a state of atrial "stunning" immediately after cardioversion, which is considered a thrombogenic milieu in which new thrombus formation and increased or de novo appearance of LA spontaneous echocardiographic contrast have been observed. Furthermore, embolic events have been reported after cardioversion despite exclusion of preexisting LA thrombus by TEE. These studies strongly suggest an alternative mechanism for embolism after cardioversion, ie, atrial stunning with worsened atrial appendage function and enhanced thrombogenesis. Recent studies have shown the safety of a TEE-guided anticoagulation approach in which exclusion of preexisting LA thrombus by TEE enables early cardioversion without the need for the standard 3 weeks of systemic anticoagulation. The importance of maintaining therapeutic anticoagulation has been further emphasized. Although preliminary observational studies of TEE-guided cardioversion are encouraging, there has been no prospective, randomized trial comparing the two strategies of anticoagulation management. The Assessement of Cardioversion Utilizing Transesophageal Echocardiography (ACUTE) pilot study randomized 126 patients from 10 sites and showed the feasibility and safety of the larger scale study. A larger multicenter, prospective randomized trial is now underway and is expected to randomize a total of 3,000 patients. The results of the ACUTE study will definitively establish the safest and the most cost-effective way to manage anticoagulation for elective cardioversion.
Anticoagulants↗
The effect of technical factors on the quality of pulmonary venous flow from the transverse and longitudinal imaging planes with transesophageal echocardiography.
Right and left upper pulmonary venous flow is usually assessed with monoplane transesophageal echocardiography (TEE) in the transverse imaging plane. Pulmonary venous flow in the transverse imaging plane may be relatively difficult to record because of the larger angle between the pulmonary vein and the transducer beam. To compare the quality of echocardiographically derived Doppler flows of the right and left upper pulmonary veins between the longitudinal and transverse imaging planes with TEE, we performed pulsed-wave Doppler TEE of both upper pulmonary veins in transverse and longitudinal imaging planes in 36 patients with various diseases. We also recorded a quality index for each flow profile and the angle between the transducer beam and the pulmonary vein. The quality index of the left pulmonary venous flow assessed with the longitudinal and transverse imaging planes was similar in 35 (95%) of 36 patients, whereas the longitudinal imaging plane was superior to the transverse plane in one patient (3%). In contrast, the quality index of the right pulmonary venous flow assessed with the longitudinal and transverse imaging planes was similar in only 19 (53%) of 36 patients, whereas in 17 patients (47%) the longitudinal imaging plane was superior to the transverse imaging plane. The quality index had a significant effect on the Doppler flow recordings; suboptimal-quality flow recordings significantly underestimated the pulmonary venous diastolic flow integrals. The left atrium was larger in those patients with unobtainable flows than in those patients with exclusively obtainable flows (p < 0.001). The angle between the sample volume and the right pulmonary vein was larger in the transverse imaging plane than in the longitudinal plane (p < 0.001). In conclusion, the longitudinal imaging plane is generally superior to the transverse imaging plane for assessing right pulmonary venous flow and is recommended for performing a comprehensive assessment of pulmonary venous flow. The ability to obtain quality images and accurate assessment of flow may be related to the size of the left atrium and angle of the pulmonary vein.
Adult↗
Reference values for normal adult transesophageal echocardiographic measurements.
Normal transesophageal echocardiographic measurements have not been presented previously relative to the effects of age, sex, and body surface area. This comparison was obtained by measuring cardiac and aortic dimensions in 60 patients (20 to 75 years old; 33 women) with normal transesophageal echocardiograms. We found a variable and usually important relationship between body surface area and 11 of 20 structures measured. A gender effect was not significant after indexing for body surface area for all but one structure. Age correlated with the diameter of the aortic root, descending aorta, superior vena cava, and right pulmonary artery. Similar dimensions were noted for certain paired structures as the two atria, the mitral and tricuspid annuli, and the aortic root and right ventricular outflow tract. Although multiple factors underlie what is normal in a given individual, our reference values serve to facilitate recognition of cardiac and aortic disease.
Adult↗
Detection of fibrous strands on prosthetic mitral valves with transesophageal echocardiography: another potential embolic source.
Patients with prosthetic mitral valves (MVR) have an increased incidence of cardiac embolic events, but the causes of these emboli have not been determined. Fibrous strands, detected by transesophageal echocardiography (TEE) on the left atrial side of MVRs, may be embolic precursors in these patients. However, the incidence and clinical significance of these strands are unknown. We reviewed the charts of 76 consecutive patients with MVRs who underwent a total of 83 TEE studies between January 1991 and January 1992. Of the 83 studies, 39 (47%) were of bioprostheses and 44 (53%) were of mechanical prostheses. Strands were found in 15 studies (18%) and were significantly more common in mechanical prostheses (32% vs 3%; p < 0.001). Embolic events occurred in 53% of patients with strands compared with only 18% of those without (p < 0.01). Strands were not associated with left atrial spontaneous echo contrast, left atrial thrombi, infection, prosthetic stenosis, severity of regurgitation, or left ventricular function. No physical evidence of these strands was found in the one native and three prosthetic valves examined visually during the study at the time of surgery. The data support the hypothesis that TEE evidence of strands is associated with a higher incidence of embolic events and indicate the potential for formation of intracardiac emboli on MVRs.
Bioprosthesis↗
Visualization of acute pulmonary emboli by transesophageal echocardiography.
This report describes a patient who became hypoxic and hypotensive while awaiting cardiac surgery. An urgent transesophageal echocardiogram in the operating room showed a mass at the junction of the main and right pulmonary arteries consistent with thrombus. The thrombus was removed surgically, and the patient then had a successful aortic valve replacement. Transesophageal echocardiography is therefore useful in the evaluation of the critically ill patient.
Acute Disease↗
Detection and evaluation of intrapulmonary vascular shunt with "contrast Doppler" transesophageal echocardiography.
Contrast echocardiography is useful for detecting intrapulmonary right-to-left shunt lesions. In a patient with suspected pulmonary arteriovenous fistula, contrast transesophageal echocardiography was used to demonstrate the presence of a right-to-left shunt. By use of a combination of two-dimensional echocardiography, contrast injection, and pulsed Doppler echocardiography, each pulmonary vein was successfully interrogated for evidence of contrast shunting. This case demonstrates that contrast transesophageal echocardiography is useful for the detection of intrapulmonary fistulas and that it has the potential for localization of the shunt lesion.
Arteriovenous Malformations↗
Left ventricular volume calculation with integrated backscatter from echocardiography.
Integrated backscatter analysis (IB) is a new echocardiographic method for automatically differentiating tissue from blood on the basis of differences in the amplitude of reflected ultrasound. Left ventricular volume was estimated with IB by use of a modification of Pappus' theorem and a summated ellipsoid method. IB measurements correlated well with a standard biplane area-length method derived off-line from endocardial borders drawn by hand from the same echocardiographic data (y = 1.09 x - 35, r = 0.95). Integrated backscatter measurement of ventricular volume derived from six imaging planes with both the Pappus' rule and the summated ellipsoid methods correlated well with magnetic resonance imaging volume estimates (r = 0.91 and r = 0.90, respectively), whereas use of one imaging plane correlated less well (r = 0.75). Automated analysis of integrated backscatter differentiates tissue from blood sufficiently to allow accurate volume calculations compared with magnetic resonance imaging and to standard hand-drawn echo techniques. This method provides accurate measurement of left ventricular volumes that should be useful in clinical hemodynamic assessments.
Adolescent↗
The frequency of acquisition and quality of images obtained by transesophageal echocardiography: a prospective study of 100 consecutive cases.
Although transesophageal echocardiography is capable of generating detailed images of the heart and aorta, the quality of these images and the frequency of their acquisition has not been previously defined. We performed monoplane transesophageal echocardiograms in 100 consecutive patients to determine the quality and frequency of acquisition of 10 standard, transverse views of the heart and aorta. Each image was graded for quality by ascribing a value from 0 (poor quality or not obtained) to 3 (excellent quality). The effect of age on image acquisition and quality was determined for patients less than or equal to 60 years (n = 54) versus greater than 60 years old (n = 46). For the 10 image planes, the average image quality score and the frequency of image acquisition (%) was (1) 2.23 and 100% for the four-chamber view, (2) 1.96 and 98% for the right ventricular inflow view and coronary sinus, (3) 2.17 and 99% for the five-chamber view, (4) 1.80 and 84% for the aortic valve short axis, (5) 1.54 and 82% for the mitral valve short axis, (6) 1.84 and 91% for the mid-left ventricular short axis, (7) 1.02 and 59% for the left ventricular apical short axis, (8) 1.79 and 93% for the ascending aorta, (9) 1.23 and 77% for the aortic arch, and (10) 1.88 and 92% for the descending thoracic aorta view. Ascending aorta and aortic valve short-axis views were obtained with a significantly higher frequency in patients less than or equal to 60 years old.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Age-related prevalence of valvular regurgitation in normal subjects: a comprehensive color flow examination of 118 volunteers.
We prospectively assessed the influence of aging on the prevalence of valvular regurgitation by using color flow imaging. One hundred eighteen healthy volunteers (21 to 82 years old) had a two-dimensional Doppler echocardiographic study that included color flow imaging to assess valvular regurgitation and that was semiquantitated by mapping the dimensions of the color flow regurgitant jet in orthogonal views. The subjects were divided into two groups: group 1 consisted of subjects who were younger than 50 years old (n = 61), and group 2 consisted of subjects who were at least 50 years old (n = 57). Mitral regurgitation was detected in 57 (48%) of the 118 subjects: 24 subjects (39%) in group 1 and 33 subjects (58%) in group 2. The severity of mitral regurgitation was trivial to mild. Aortic regurgitation was detected in 13 (11%) of the 118 subjects, all in group 2. The severity was trivial to mild. Tricuspid regurgitation was detected in 77 (65%) of the 118 subjects: 35 (57%) in group 1 and 42 (74%) in group 2. The severity was trivial to mild. Pulmonary regurgitation was detected in 24 (31%) of 78 subjects: nine (22%) in group 1 and 15 (41%) in group 2. The severity was trivial. These findings suggest that valvular regurgitation of a trivial or mild degree is a frequent finding in normal subjects and that it increases with age.
Adult↗
A comparison of flow convergence with other transthoracic echocardiographic indexes of prosthetic mitral regurgitation.
Prosthetic shadowing of the left atrium may prevent detection of mitral regurgitation during transthoracic echocardiography. In 60 patients with mitral valves, Carpentier-Edwards (n = 20), St. Jude (n = 22), and cage-ball (n = 18), we blindly evaluated the accuracy of three transthoracic Doppler signs of significant (> 2+) mitral regurgitation: (1) color Doppler flow convergence, (2) a color Doppler jet of significant regurgitation in the left atrium, and (3) an intense continuous wave Doppler signal. All 60 patients had transesophageal echocardiography, 26 had cardiac catheterization, and 28 had surgery. The sensitivity and specificity of flow convergence for significant regurgitation by transesophageal echocardiography was 73% and 70%, respectively, compared with 33% and 93% for left atrial color Doppler, and 15% and 97% for continuous wave Doppler. The sensitivity of flow convergence in Carpentier-Edwards, St. Jude, and cage-ball valves was 80%, 73%, and 67%, respectively; whereas the sensitivity of left atrial color Doppler was 70%, 27%, and 0%, and the sensitivity of continuous wave Doppler was 33%, 0%, and 13%. Flow convergence was the only sign of significant regurgitation in 12 of 30 patients (40%); 10 of these patients had mechanical valves. We conclude flow convergence is a more sensitive, though less specific, predictor of significant mitral regurgitation than color Doppler, spatial mapping of the left atrium, and continuous wave Doppler, especially when a mechanical valve is present.
Adult↗
Effect of sample volume location on Doppler-derived transmitral inflow velocity values.
In 25 patients with acute myocardial infarction and in 25 normal subjects, pulsed-wave Doppler echocardiography was performed in the apical four-chamber view with the sample volume first between the mitral leaflet tips and then at the mitral anulus. The early filing wave (E) and late filling wave (A) peak velocities measured from Doppler strip charts were significantly (p less than 0.001) higher at the tips in both groups. E velocity increase was greater than A velocity increase, producing a significantly (p less than 0.001) higher E/A velocity ratio at the tips than at the anulus. The deceleration time was longer at the tips than at the anulus (p less than 0.001) in both groups. Therefore it is important to know sample volume location in the interpretation of mitral inflow velocity. It is critical to maintain the same sample volume location in serial assessments of left ventricular diastolic filling characteristics.
Adult↗
Doppler assessment of pulmonary venous flow in healthy subjects and in patients with heart disease.
Pulmonary venous flow as assessed by Doppler echocardiography is a current topic of investigation. Pulmonary venous flow has been used recently as part of a comprehensive assessment of left ventricular diastolic filling dynamics in restrictive myocardial diseases and constrictive pericarditis. Abnormalities of flow have been described in dilated cardiomyopathy, congenital heart disease, and arrhythmias. With the advent of transesophageal echocardiography, pulmonary venous flow can be readily obtained in all patients by pulsed-wave Doppler echocardiography. Recently, it has been used to assess the severity of mitral regurgitation and to estimate mean left atrial pressure. This article emphasizes the utility, physiology, and technique of measuring pulmonary venous flow with Doppler echocardiography in health and in disease.
Blood Flow Velocity↗
Importance of sampling both pulmonary veins in grading mitral regurgitation by transesophageal echocardiography.
Pulmonary venous flow patterns have been used to assess severity of mitral regurgitation; however, the issue of which pulmonary veins to sample has not been determined. We performed pulsed wave Doppler transesophageal echocardiography of both the left and right upper pulmonary veins in 80 patients who had mitral regurgitation determined by independent transesophageal echocardiography color flow mapping. Pulmonary venous flow patterns, peak systolic and diastolic flow, and the presence of reversed systolic flow were compared between the left and right pulmonary veins for each grade of mitral regurgitation. Flow patterns were discordant in 20 (25%) of the 80 patients. Of the 43 patients with 4+ mitral regurgitation, there was discordant flow in 16 (37%) of the patients with mainly reversed systolic flow in the right upper vein, while there was blunted or normal systolic flow in the left upper vein. Of the 16 patients with discordant flows, 14 had eccentric jets, mainly anteromedial jets. We conclude that if discordant flow can occur in 25% of patients with mitral regurgitation and in 37% of patients with 4+ mitral regurgitation, then both pulmonary veins must be evaluated when assessing the severity of mitral regurgitation with pulsed wave Doppler transesophageal echocardiography.
Adult↗
Two-dimensional and Doppler echocardiographic assessment of infiltrative cardiomyopathy.
Infiltrative cardiomyopathies can be divided by disease into infiltrative and storage disorders that show an increase in ventricular wall thickness caused by infiltration of pathologic substances between cells, as with amyloid and sarcoid, or deposition within cells, as with iron, glycogen, and lipid. Two-dimensional and Doppler echocardiography are powerful noninvasive tools in the assessment of the anatomic and functional characteristics of these disorders. With cardiac amyloidosis as the prototype, the constellation of findings of a small or normal left ventricular cavity size; markedly increased thickness of the ventricular walls, associated with a highly abnormal texture; and biatrial enlargement make up its characteristic appearance. However, there is a wide spectrum of abnormalities in this disorder, depending on the stage and duration of heart involvement. Doppler assessment of diastolic function is frequently abnormal in cardiac amyloidosis. Cardiac sarcoidosis usually is evident by a dilated segmental cardiomyopathy with regional wall abnormalities. Similarly, hemochromatosis appears as a dilated cardiomyopathy with normal wall thickness. The echocardiographic appearance of glycogen and glycolipid storage diseases is similar to cardiac amyloidosis, and biochemical analysis may be necessary for differentiation. Thus echocardiography is an important tool in the characterization of infiltrative cardiomyopathies.
Amyloidosis↗
Color Doppler and two-dimensional echocardiographic determination of the mechanism of aortic regurgitation with surgical correlation.
The character of the color flow Doppler jet provides information on the mechanism and pathologic elements of valve dysfunction. This has been useful in the evaluation of mitral regurgitation, a repairable problem, but has not been described comprehensively for the aortic valve. The purpose of our study was to correlate the color flow Doppler characteristics of the aortic regurgitant jet and two-dimensional echocardiographic findings of valve mobility with surgical pathology. Prepump intraoperative echocardiography and color flow Doppler echocardiography were performed on 124 patients with aortic regurgitation and used to categorize leaflet motion as excessive, restricted, or normal, jet direction as eccentric or central, and jet origin between the cusps as eccentric, central, or diffuse. Bicuspid disease and tricuspid aortic valve prolapse were associated with excessive valve mobility and eccentric jet direction and origin. Conversely, annular dilation, rheumatic disease, sclerosis, and perforation were associated with normal or reduced cusp mobility and a central jet direction and origin (p = 0.001). Overall, an eccentric jet direction occurred in 69% of patients with excessive cusp mobility, whereas 71% of patients with normal or reduced cusp mobility had a central jet (p = 0.001). Therefore color flow Doppler determination of the eccentricity of regurgitant jet direction and origin is useful in predicting the mechanism and disease of aortic valve dysfunction. These observations may suggest the presence of prolapse and thus the potential for aortic valve repair.
Adolescent↗
Left and right atrial transport function after the Maze procedure for atrial fibrillation: an echocardiographic Doppler follow-up study.
OBJECTIVES: We evaluated atrial transport function after the Maze procedure in long-term follow-up and compared left and right atrial function in Maze patients with that of healthy age-matched controls using echo Doppler techniques. BACKGROUND: The Maze procedure is designed to eliminate atrial fibrillation, restore normal sinus rhythm, and preserve atrial contraction. Initial data indicate that atrial transport function is restored in most patients undergoing the Maze procedure. The long-term echo Doppler evaluation of patients after the Maze procedure has not been well described. METHODS: We performed pulsed-wave Doppler and two-dimensional echocardiographic studies on 31 patients (24 men, mean age 53.8 years) who underwent the Maze procedure and who had a follow-up study greater than 3 months (mean 16.5 months) after the procedure. Measurements included peak left ventricular and right ventricular inflow A-wave velocity, maximum and minimum left atrial and right atrial areas, and fractional area change of the left and right atria. Results were compared with those obtained from 15 age-matched control subjects (11 men, mean age 53.8 years). RESULTS: Twenty-two patients (71%) had left atrial function shown by the presence of left ventricular inflow A-wave, and 25 patients (81%) had right atrial function shown by the presence of right ventricular inflow A-wave on Doppler echocardiography. The left ventricular inflow A-wave velocity was significantly lower than that of age-matched controls (37.5 +/- 15.5 versus 61.0 +/- 13.9 cm/sec; p < 0.001), whereas the right ventricular inflow A-wave velocity did not significantly differ between patients and control subjects (35.4 +/- 9.9 versus 35.3 +/- 4.9 cm/sec; p = Not significant). Although left and right atrial areas decreased significantly after the procedure, there was no significant change in the fractional area change which was smaller in Maze patients than control individuals. CONCLUSIONS: (1) In long-term follow-up of 16.5 months after the Maze procedure, left atrial systolic function was preserved in 71% of our patients and right atrial systolic function was preserved in 81%; (2) the left ventricular inflow peak A-wave velocity after Maze is considerably less than that in age-matched controls; and (3) left and right atrial sizes decreased after the procedure with no change in the fractional area change. These findings suggest that the Maze procedure is effective in restoring atrial function in the majority of patients; however, restored function is less than in control individuals.
Adult↗