Search

Mitral regurgitation (MR) severity is routinely assessed by Doppler color flow mapping, which is subject to technical and hemodynamic variables. Vena contracta width may be less influenced by hemodynamic variables and has previously been shown to correlate with angiographic estimates of MR severity. This study was performed to compare mitral vena contracta width by multiplane transesophageal echocardiography (TEE) with simultaneous quantitative Doppler echocardiography in 35 patients with MR. The vena contracta width was measured at the narrowest portion of the MR jet as it emerged through the coaptation of the leaflets; it was identified in 97% of the patients. Vena contracta width correlated well with regurgitant volume (R2 = 0.81) and regurgitant orifice area (R2 = 0.81) by quantitative Doppler technique. A vena contracta width > or = 0.5 cm always predicted a regurgitant volume >60 ml and an effective regurgitant orifice area > or = 0.4 cm2 in all patients. A vena contracta width < or = 0.3 cm always predicted a regurgitant volume <45 ml and a regurgitant orifice area < or = 0.35 cm2. Thus, vena contracta width by multiplane TEE correlates well with mitral regurgitant volume and regurgitant orifice area by quantitative Doppler echocardiography and provides a simple method for the identification of patients with severe MR. [ABSTRACT FROM AUTHOR]

Background: Although transesophageal echocardiography (TEE) is more sensitive than transthoracic echocardiography (TTE) in detecting echocardiographic evidence of infective endocarditis (IE), the impact of TEE on the clinical diagnosis of IE has not been clearly delineated., Methods and Results: We studied 112 patients with 114 suspected episodes of IE over a 6-year period who underwent both TTE and TEE during their diagnostic evaluation. Using the results of these studies along with clinical and microbiologic data, we attempted to determine the incremental value of TEE to the Duke Endocarditis Diagnostic Criteria. Patients were initially classified into a diagnostic category of the Duke criteria with TTE data, and then the diagnostic classification was reconsidered with TEE data. A diagnostic category reassignment occurred in 25 of 114 episodes of IE evaluated when TEE results were incorporated into the evaluation with the Duke criteria (22 patients were reclassified from possible IE to definite IE whereas 3 patients were reclassified from rejected to possible IE). Diagnostic reclassification occurred in 9 (11%) of the 80 episodes of suspected IE with native cardiac valves and 13 (34%) of 34 episodes with prosthetic cardiac valves. Most patients reclassified from possible IE to definite IE with TEE data (19 of 22) had an intermediate clinical likelihood of IE, whereas 92% of patients had negative TTE results. Pathologic examination of valvular tissue in 22 of the 114 episodes of suspected IE revealed that the positive predictive value of the Duke criteria with TEE data for diagnosis of IE was 85% in patients with native valves and 89% in patients with prosthetic valves., Conclusions: When clinical evidence of IE is present, TEE improves the sensitivity of the Duke criteria to diagnose definite IE. TEE data appears to be especially useful for the diagnostic evaluation of patients with suspected IE who have prosthetic valves.

Objectives: We used color Doppler flow mapping to determine whether vena contracta width (VCW) is a load-independent measure of the severity of mitral regurgitation., Background: VCW has been proposed to be a relatively load-independent measure of mitral regurgitation severity in flow models using a fixed orifice. However, in patients with mitral regurgitation, VCW may not be load independent because of a dynamic regurgitant orifice., Methods: VCW, effective regurgitant orifice area and regurgitant volume were measured by quantitative Doppler mapping in 31 patients with chronic mitral regurgitation at baseline and during nitroprusside infusion. Patients with rheumatic heart disease, annular calcification or endocarditis were considered to have a fixed regurgitant orifice, whereas patients with mitral valve prolapse, dilated cardiomyopathy or ischemia were considered to have a dynamic regurgitant orifice., Results: Systolic blood pressure (148 +/- 27 to 115 +/- 25 mm Hg) and end-systolic wall stress (121 +/- 50 to 89 +/- 36) decreased with nitroprusside (p < 0.05). Although nitroprusside did not significantly change mean values for VCW (0.5 +/- 0.2 to 0.5 +/- 0.2 cm), regurgitant volume (69 +/- 47 to 69 +/- 56 ml) or effective regurgitant orifice area (0.5 +/- 0.4 to 0.5 +/- 0.6 cm2), individual patients exhibited marked directional variability. Specifically, VCW decreased in 16 patients (improved mitral regurgitation), remained unchanged in 7 patients and increased in 8 patients (worsened mitral regurgitation) with nitroprusside. Also, the VCW response to nitroprusside was concordant with changes in effective regurgitant orifice area and regurgitant volume, and was not different between dynamic and fixed orifice groups., Conclusions: Contrary to the results from in vitro studies, VCW is not load independent in patients with mitral regurgitation caused by dynamic changes in the regurgitant orifice. The origin of mitral regurgitation does not predict accurately whether the regurgitant orifice is fixed or dynamic. Finally, short-term vasodilation with nitroprusside may significantly worsen the severity of mitral regurgitation in some patients.

Background: Improvement in the left ventricular outflow tract (LVOT) gradient has been used as a means of assessing response to therapy in patients with hypertrophic obstructive cardiomyopathy (HOCM). To our knowledge, no data exist regarding the spontaneous day-to-day variability of the LVOT gradient in patients with HOCM. Defining the magnitude of such variability is critical to properly understand how much improvement in LVOT gradient must be present to invoke a therapeutic response., Methods and Results: We studied the spontaneous variation in the continuous-wave, Doppler-derived pressure gradient on 5 consecutive days in 12 HOCM patients and 5 aortic stenosis control subjects. While in some patients the day-to-day variability in resting gradient was small, in others it varied markedly. The 95% confidence interval for attributing a change in LVOT gradient to factors other than random variation is +/-32 mm Hg for resting gradient and +/-50 mm Hg for provoked gradient. The mean coefficient of variation for gradient across 5 days for the group was 0.52+/-0.33 for resting gradient and 0.46+/-0.16 for provoked gradient. The day-to-day variability in pressure gradient could not be explained by changes in heart rate, blood pressure, or left ventricular end-diastolic dimension, each of which had a coefficient of variation <.11. Moreover, technical factors related to the performance or interpretation of the studies did not account for it because the coefficient of variation for gradient in aortic stenosis was <10% and interobserver and intraobserver agreement was excellent (r=.96 and .98, respectively)., Conclusions: The LVOT pressure gradient varies considerably from day to day in stable patients with HOCM. A single measurement of pressure gradient is not adequate to define the severity of dynamic LVOT obstruction in HOCM.

Unlabelled: This study was performed to determine whether gated equilibrium radionuclide angiogram measurements of left ventricular function during rest and exercise add independent information to clinical and catheterization data in predicting cardiac death., Methods and Results: The study population consisted of 863 consecutive patients undergoing exercise gated equilibrium radionuclide angiography within 90 days of cardiac catheterization with data prospectively entered into the Duke Cardiovascular Database. All patients were symptomatic, medically treated, with significant coronary artery disease and had undergone follow-up for < or = 6 yr. A univariable and multivariable Cox regression analysis was utilized to evaluate the independent power in predicting 147 (17.0%) cardiac deaths. This risk-adjusted analysis revealed that only rest and exercise ejection fraction as well as maximum workload contained independent prognostic information; the nuclear variables contributed 63% of the total information within the model. A multivariable model including exercise ejection fraction and clinical history variables provided slightly more prognostic information than the combination of cardiac catheterization and clinical data., Conclusion: Multigated equilibrium radionuclide angiography is a key predictor of cardiac death when compared to clinical and cardiac catheterization data in patients with symptomatic, medically treated coronary artery disease. Thus, long-term outcome for patients may be determined by utilizing this noninvasive tool even when clinical and cardiac catheterization data are also available.

Objective: Our purpose was to assess the accuracy of measurements of flow velocity and volume flow rate in an in vitro phantom and in healthy human volunteers using a cardiac-gated, segmented K-space, fast cine phase-contrast (PC) MR imaging technique with view sharing (fast PC). We compared this method with conventional cine PC MR imaging and Doppler sonography., Subjects and Methods: Pulsatile flow was generated in a flow phantom that consisted of a cylindric tube having various degrees of tapered stenosis. Phase-encoded velocity maps were obtained using cine PC and fast PC MR imaging. Doppler sonography was also performed. Measurements of aortic and pulmonary artery peak systolic and minimum diastolic velocity and volume flow rate were then compared in eight healthy volunteers using the three imaging techniques., Results: We found excellent agreement between fast PC and cine PC measurements of peak systolic velocity when regions of interest were drawn to exclude vessel margins (r > .99 for phantom studies, and r = .80 for human studies). Correlation between minimum diastolic velocity measurements by MR imaging was limited by noise that resulted from high encoding velocity settings. However, such correlation improved with signal averaging. When compared with predicted values of volume flow rates, both cine PC (r > .99) and fast PC (r = .97) MR imaging were more accurate than Doppler sonography (r = .78) in vitro. Measurements of cardiac output were adversely affected by low signal to noise, especially during diastole; estimates based on systolic forward flow resulted in better agreement between the two MR imaging methods., Conclusion: Fast PC MR flow quantification may prove to be a useful adjunct to routine MR studies for measurements of peak flow velocity. However, estimates of volume flow rate using fast PC MR imaging are limited because of increased noise during low diastolic flow as well as edge artifacts.

This article examines the use of transesophageal echocardiography (TEE) in the assessment of prosthetic heart valves. A summary of the commonly used artificial valves and their physiologic regurgitant flow patterns, as identified by color Doppler imaging, is presented. The hemodynamic evaluation of prosthetic valve stenosis using Doppler techniques is reviewed, and the diagnostic utility of TEE in identifying the complications of cardiac prostheses is discussed.

Although it has been shown that a hypotensive response during dobutamine stress echocardiography is not a marker of coronary artery disease, the mechanism of this response remains unclear. We hypothesize that hypotension during dobutamine stress echocardiography is not related to the development of dynamic intraventricular obstruction. The development of left ventricular outflow obstruction was defined as a late-peaking Doppler velocity profile that exceeded baseline outflow velocity by at least 1 m/sec in 104 consecutive patients undergoing dobutamine stress echocardiography. Left ventricular outflow obstruction was seen in 13% of 15 patients with a hypotensive response (group 1) and in 13% of 89 patients without a hypotensive response (group 2). The mean baseline systolic blood pressure was 157 +/- 21 mm Hg in group 1 compared to 139 +/- 25 mm Hg in group 2 (p = 0.008). An ischemic response to dobutamine infusion as manifested by the development of new or worsening wall motion abnormalities was seen in 40% of group 1 patients and 34% of group 2 patients (p = 0.77). These data demonstrate that a hypotensive response is not related to the development of dynamic intraventricular obstruction during dobutamine stress echocardiography. Rather, there is a significant association between a higher baseline systolic blood pressure and a hypotensive response during dobutamine infusion.

The development of hypotension during various exercise stress tests has been correlated with the presence of multivessel coronary artery disease and impaired left ventricular contractility. Hypotension may also occur during dobutamine stress echocardiography; however, its anatomic and functional significance remains unknown. As part of an ongoing study of restenosis, dobutamine stress echocardiography and diagnostic cardiac catheterization were performed on the same day in 105 outpatients approximately 6 months after percutaneous coronary revascularization (balloon angioplasty or directional coronary atherectomy) to determine the anatomic and functional significance of dobutamine-induced hypotension. Dobutamine was infused in stepwise increments to a maximum rate of 30 micrograms/kg/min. Hypotension was defined as a reduction in systolic blood pressure of > or = 15 mm Hg. Anatomic abnormalities were defined by quantitative coronary angiography and functional abnormalities by digitized two-dimensional stress echocardiography. Clinical, angiographic, hemodynamic, and electrocardiographic data underwent multivariable regression analysis to determine their ability to predict independently the development of dobutamine-induced hypotension. Dobutamine-induced hypotension was not associated with the presence of severity of coronary artery disease or with echocardiographic wall motion abnormalities. Univariable predictors of stress-induced hypotension included high baseline systolic blood pressure, advanced age, and high left ventricular ejection fraction. Only a high baseline systolic blood pressure contributed independent predictive information in multivariable stepwise logistic regression analysis. Therefore, the development of hypotension during dobutamine stress echocardiography, unlike that during traditional exercise stress tests, is not associated with the presence of significant coronary artery disease or left ventricular dysfunction.

Objectives: This study was performed to examine the effect of dobutamine stress echocardiography on mitral regurgitation and to test the hypothesis that mitral regurgitation will increase in patients with an ischemic response., Background: New or worsening mitral regurgitation during stress testing has been proposed as a marker of ischemia. However, it is unclear whether ischemia induced by dobutamine is associated with mitral regurgitation because the hemodynamic effects of dobutamine may vary with regard to mitral regurgitation, depending on left ventricular function and maximal dose attained., Methods: Dobutamine stress echocardiography was performed in 102 consecutive patients with suspected or known coronary artery disease. Color flow Doppler was used to determine the presence and change in mitral regurgitation at baseline and peak dobutamine infusion (up to 40 micrograms/kg body weight per min). The mitral regurgitation color flow Doppler area was semiquantitatively graded as mild (< 4 cm2), moderate (4 to 8 cm2) or severe (> 8 cm2). Patients were assigned to ischemic and nonischemic groups according to the dobutamine stress echocardiographic results., Results: The two groups achieved the same maximal dose and demonstrated similar blood pressure and heart rate responses to dobutamine infusion. Only two patients developed new mitral regurgitation during dobutamine infusion, and both had a normal dobutamine echocardiographic result. More patients without ischemia had no mitral regurgitation compared with patients with ischemia. There was an insufficient number of patients with coronary angiographic data to determine the effects of mitral regurgitation on the sensitivity and specificity of dobutamine stress echocardiography. Of 23 patients with a rest ejection fraction < 50%, 61% had an improvement in mitral regurgitation grade compared with 25% of patients with a rest ejection fraction > or = 50% (p < 0.02)., Conclusions: These data indicate that although dobutamine infusion often improves mitral regurgitation in patients with left ventricular dysfunction during stress echocardiography, it does not induce or worsen mitral regurgitation in those who demonstrate an ischemic response. Future studies are necessary, with large numbers of patients, to determine the effects of mitral regurgitation on the sensitivity and specificity of dobutamine stress echocardiography.

Transesophageal echocardiography and diagnostic cardiac catheterization were performed in 36 patients with symptomatic mitral stenosis to assess the incidence and significance of systolic flow reversal in the pulmonary veins. Mitral regurgitation was graded by contrast ventriculography, and left atrial pressure was directly measured after transseptal puncture. Pulmonary venous flow was recorded with transesophageal Doppler imaging from the left upper pulmonary vein. Early systolic flow reversal was identified in 11 patients (31%) and began an average of 58 +/- 13 ms after QRS onset. This pattern correlated strongly with the presence of atrial fibrillation or flutter. Late systolic flow reversal was identified in 8 patients (22%), beginning an average of 245 +/- 46 ms after the QRS complex. These patients had higher left atrial V-wave pressure (36 +/- 10 vs 29 +/- 8 mm Hg; p < 0.05) and V-wave peak-X-descent trough (18 +/- 7 vs 11 +/- 5 mm Hg; p < 0.01) than patients without systolic flow reversal. Neither pattern of pulmonary venous flow reversal was related to the severity of angiographic mitral regurgitation. Systolic reversal of pulmonary venous flow is not specific for angiographically severe mitral regurgitation in patients with mitral stenosis. Similar limitations to pulmonary venous flow analysis likely apply to other patient groups with elevated left atrial pressure and poor left atrial compliance.

Echocardiography and thallium-201 imaging with coronary vasodilators such as dipyridamole have been shown to be useful in detecting the presence and prognostic significance of coronary artery disease. Adenosine, a potent and direct coronary vasodilator, has a shorter physiologic half-life than dipyridamole, which exerts its effect by blocking the cellular uptake of adenosine. Because of the potential advantage of dipyridamole, we undertook this study to determine the correlation of adenosine echocardiography with thallium scintigraphy. Forty-two patients (18 men and 24 women; mean age 64) who were unable to undergo treadmill exercise and were known or suspected to have coronary artery disease were studied. A baseline echocardiogram was obtained in four standard views followed by adenosine infusion at a rate of 140 micrograms/kg/min for 6 minutes. Thallium-201 was administered 3 minutes into the infusion while a second echocardiogram was performed. Thallium-201 imaging was begun immediately after the infusion of adenosine and repeated 4 hours later. Sixteen patients underwent coronary angiography within 1 month of the adenosine echocardiogram and thallium-201 study. At the peak infused dose of adenosine there was a significant increase in heart rate (12 beats/min; p = 0.0001) and rate-pressure product (1.3 x 10(3) beats/min x mm Hg; p = 0.02) and statistically insignificant decreases in systolic and diastolic blood pressures. Sixty-two percent of patients experienced side effects during the adenosine infusion, with chest pain, shortness of breath, and flushing occurring most frequently. These side effects resolved within 1 to 2 minutes after the infusion was stopped. Ischemic electrocardiographic changes occurred in 19% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipoprotein from the outer membrane of Escherichia coli and its synthetically prepared N-terminal lipopeptide segments Pam3Cys-Ser-Ser-Asn-Ala and Pam3Cys-Ser, as well as lipoprotein from other Enterobacteriaceae, constitute potent polyclonal B lymphocyte activators. Here, we demonstrate that these compounds were also able to stimulate human and murine leukocytes: in murine macrophages, we could show the induction of interleukin 1 release by the mitogens, as measured in the thymocyte proliferation assay. Moreover, murine peritoneal exudate cells were stimulated to secrete prostaglandins E2 (PGE2) and F2 alpha (PGF2 alpha). The effect of Pam3Cys-Ser on the murine macrophage cell line P388D1 was also tested: the compound induced an increase in proliferation, as measured by a thymidine incorporation assay. In addition, the cell line could be induced to release IL 1 into the supernatant. Correspondingly, induction of IL 1 release could also be demonstrated in human mononuclear cells. Our results demonstrate that the two novel synthetic lipopeptides are potent stimulators for human monocytes and murine macrophages. These findings may be important for the elucidation of the role of these bacterial surface components in the course of bacterial infections.

The effects of bafilomycin macrolide antibiotics on primary lymphocytes and on tumor cell lines were investigated. Bafilomycin A markedly suppressed DNA, RNA, and protein synthesis in splenocyte cultures of several inbred mouse strains. Bafilomycins were also inhibitory towards cultures of concanavalin A- or lipopolysaccharide-activated murine spleen cells, and inhibited the mitogen-induced differentiation of B lymphocytes into immunoglobulin-secreting plasma cells. Corresponding results were obtained in human cell cultures. A hydrolysis product of the bafilomycin molecule was inactive. Bafilomycin also inhibited the growth of various lymphoid cell lines, the B cell line BCL1, the macrophage cell lines J774 and P338D1, and the T cell line EL4. The sensitivity of the tumor cell lines increased when, simultaneously with bafilomycin, mitogens were applied to the cell cultures. The immunosuppressive action of cyclosporin A could be enhanced by bafilomycin, which could be of importance for the elucidation of the molecular mechanism of T cell suppression, and for applied medical research.