Noninvasive intracardiac pressure measurement using Doppler ultrasound.
Explore the source record for details and available documents.
Blood Pressure Determination↗
Biomedical subjects
R L Popp
Publications and source records attributed to R L Popp.
Echocardiographic recognition of paraseptal structures.
Improved echocardiographic equipment provides detailed images of the heart and shows anatomic paraseptal structures previously not well defined. Echocardiograms were analyzed from 33 patients who later underwent cardiac transplantation, and the paraseptal structures noted were correlated with the pathologic specimens. Patterns associated with right ventricular chordae tendineae, the moderator band and the posterior papillary muscle are illustrated. Hypertrophic and fibrotic right ventricular trabeculae and left ventricular paraseptal bands are noted. These structures can be specifically sought and identified using the current generation of echocardiographs, thereby avoiding potential problems of septal definition and measurement.
Adolescent↗
Comparative recognition of left ventricular thrombi by echocardiography and cineangiography.
Studies performed in 47 patients, 11 of whom underwent surgery for aneurysmectomy and 36 of whom underwent cardiac transplantation, were reviewed to assess the diagnostic accuracies of cross sectional echocardiography and cineangiography in detecting left ventricular mural thrombi and the effect of anticoagulation treatment on the incidence of such thrombi. Cross sectional echocardiography in 37 patients and cineangiography in 26 (16 patients were examined by both methods) were analysed independently by sets of two observers experienced in the respective methods. All four observers were blinded to the pathological or surgical findings regarding mural thrombus. Mural thrombus was confirmed by pathological investigation in 14 of 47 (30%) cases; 11 of these 14 patients had intra-aneurysmal thrombi. The negative predictive value was quite good for both methods, but cross sectional echocardiography had a superior positive predictive value. This was due both to detailed soft tissue resolution by cross sectional echocardiography and to overdetection of mural thrombi by cineangiography in cases of aneurysms without mural thrombi. Mural thrombi were present in three of 20 patients with preceding anticoagulation and in 10 of 19 patients without anticoagulation. The results emphasise that cross sectional echocardiography is more reliable than cineangiography in recognising thrombi.
Adult↗
Ultrasonic tissue characterization: detection of acute myocardial ischemia in dogs.
Ultrasonic tissue characterization is a new area of investigation in the field of cardiac ultrasound. The amplitude and frequency of the ultrasound signal are normally altered as the signal penetrates through tissue. It is assumed that the amplitude distribution and frequency shift of diseased or edematous tissue are different than those of normal tissue. A statistical approach to the analysis of the unprocessed radiofrequency signal in the amplitude domain was used to study the effect of acute myocardial ischemia on the parameter mean amplitude/standard deviation of the amplitude (MSR). Ten dogs were anesthetized and underwent left lateral thoracotomy. Baseline mean MSR from the interventricular septum was 1.99 +/- 0.05, but increased by 30 min after coronary artery occlusion and started to plateau at 1 hr (mean 2.24 +/- 0.06). Reproducibility in noninfarcted myocardium (left ventricular inferoposterior wall) was good, with a mean MSR of 2.00 +/- 0.05 at baseline and 1.98 +/- 0.04 3 to 4 hr later. There was no difference in mean MSR when data were obtained through chest wall and when they were obtained directly from the surface of the heart. We conclude that statistical analysis in the amplitude domain of the unprocessed radiofrequency signal can detect acute myocardial ischemia within 30 min after coronary artery occlusion, provides reproducible measurements, and is unaffected by chest wall filtering.
Animals↗
Mildly dilated congestive cardiomyopathy.
Five patients with only mildly dilated ventricles but other features typical of congestive cardiomyopathy underwent cardiac transplantation for class IV NYHA heart failure. The findings of clinical studies, cardiac catheterization, endomyocardial biopsy, and pathologic examination of the removed hearts in this group with mildly dilated congestive cardiomyopathy (MDCM) were compared with similar data in four patients with idiopathic restrictive cardiomyopathy (IRCM) and in 10 patients with typical dilated congestive cardiomyopathy (DCM). In comparison with the other groups, patients with MDCM had a higher incidence of familial cardiomyopathy (p = .02) and a shorter symptomatic period than patients with IRCM (p less than .02). Patients with both MDCM and DCM had globular hearts (with predominant left ventricular dilatation), congestive hemodynamics and poor left ventricular contractility (ejection fraction 12% to 19%), and high incidence of ventricular thrombi. Patients with IRCM showed normal ventricular size, marked atrial dilatation, restrictive hemodynamics, mild-to-moderate decrease in left ventricular contractility (ejection fraction 29% to 55%), and absence of ventricular thrombi. Cardiac index, ventricular wall thickness, and light microscopic findings were similar in the three groups of patients. Electron microscopy showed no myofibrillar loss in patients with IRCM but mild (partial) or moderate-to-severe (almost total) myofibrillar loss in those with MDCM and DCM, respectively. We conclude that end-stage congestive cardiomyopathy may occur without significant ventricular dilatation and patients with MDCM have heart sizes intermediate between those found in IRCM and DCM but their clinical, hemodynamic, and pathologic findings are virtually identical to those of patients with typical DCM.
Adult↗
The accuracy of Doppler ultrasound measurement of pressure gradients across irregular, dual, and tunnellike obstructions to blood flow.
The accuracy of Doppler-estimated pressure gradients in the setting of irregular, multiple, and tunnellike stenoses was investigated. An in vitro model of the left ventricular outflow tract was designed to allow pulsatile flow of red cells in saline across valve orifices from 0.01 to 2.5 cm2. Simultaneous pressure gradients were estimated by both Doppler and direct-pressure manometer techniques. Gradients obtained by the two methods correlated well for valve areas in the range of clinical stenoses at pressure gradients of 10 to 150 mm Hg (r = .97 to .99). Model valves were constructed with a large orifice (0.75 to 1.25 cm2) placed beside a small orifice (0.02 to 0.25 cm2) in the same outflow tract. A distinct jet was recorded when the Doppler transducer was aligned with each orifice. Doppler-estimated gradients for each pair of large and small orifices were identical and correlated well with those measured by manometer (r = .97 to .99). Irregularly shaped orifices also provided good correlation between the two methods (r = .98 to .99). Pulsatile flow was generated through long tunnellike obstructions with cross-sectional areas varying from 0.06 to 1.25 cm2. Tunnel length varied from 0.1 to 4 cm. Tunnel areas above 0.25 cm2 gave good Doppler-to-manometer correspondence at all tunnel lengths. Doppler underestimated manometer-determined values in the 0.25 cm2 tunnel by 8% at 3 cm and by 15% at 4 cm. In the 0.06 cm2 tunnel, Doppler underestimated manometer gradients by 12%, 15%, 32%, and 42% at lengths of 1, 2, 3, and 4 cm, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Centrifugation, Density Gradient↗
A new method for assessing right-sided heart pressures using encapsulated microbubbles--a preliminary report.
A new noncatheter method for measuring pressures of the right side of the heart uses specially manufactured microbubbles of carbon dioxide injected into the peripheral venous system. Sudden expansion of these bubbles in the cardiac chambers causes bubble oscillations at a frequency that is primarily a function of surrounding pressure. The oscillations are recordable by a microphone on the chest wall. The preliminary experience has been in dogs and further development is needed before we can begin clinical testing of the method. In its current form, the potential for measuring higher systolic pressures seems better than that for lower diastolic pressures.
Animals↗
Computerized quantitative analysis of left ventricular wall motion by two-dimensional echocardiography.
Quantitative detection of left ventricular segmental wall motion abnormalities by any modality depends on the reference system used because of the dynamic geometry of contraction and cardiac motion within the thorax. To assess the feasibility and accuracy of quantitative analysis of left ventricular wall motion by two-dimensional echocardiography, we studied 61 subjects with the use of 44 different reference methods in each of three echocardiographic views: the parasternal short-axis view at the levels of the mitral valve and of the papillary muscles and an apical four-chamber view. The three major groups of reference systems used were those with a fixed external reference, a floating reference correcting for translation, and systems correcting for both translation and rotation. In the first part of this study the end-diastolic and end-systolic outlines of 20 normal subjects were stored in a computer and composite data of these 20 subjects were plotted to obtain a 95% confidence interval for measured normal fractional change for each reference method. In the second part of the project an additional prospective group of 10 normal subjects and a group of 31 "abnormal" patients had their left ventricular wall motion analyzed by similar methods and the results were compared with all the confidence intervals. One reference method was selected for each two-dimensional echocardiographic view based on the highest sensitivity and specificity found by statistical analysis; a floating-reference system including translation was found to be optimal for the apical four-chamber and parasternal short-axis views at the level of the mitral valve and a fixed external reference system was optimal for the short-axis view at the papillary level. The percent fractional shortening of radial dimensions (radial methods) and the percent fractional change in area measurements (area methods) during the cardiac cycle were also calculated at 5, 10, 20, 30 and 45 degree intervals around the outline perimeter for each subject according to each of the 44 different methods. Area methods yielded the same specificity and sensitivity as radial dimension analysis methods at 5 to 45 degree intervals. Ten normal subjects underwent repeat echocardiography within 2 days of their first study to examine day-to-day variation. Average change in mean contraction from day to day was 7% to 9% for radial methods and 9% to 13% for area methods. In conclusion, we present a computerized system for unbiased selection of optimal methods of analysis of left ventricular wall motion by two-dimensional echocardiography.(ABSTRACT TRUNCATED AT 400 WORDS)
Adult↗
Noninvasive estimation of right ventricular systolic pressure by Doppler ultrasound in patients with tricuspid regurgitation.
We evaluated the accuracy of a noninvasive method for estimating right ventricular systolic pressures in patients with tricuspid regurgitation detected by Doppler ultrasound. Of 62 patients with clinical signs of elevated right-sided pressures, 54 (87%) had jets of tricuspid regurgitation clearly recorded by continuous-wave Doppler ultrasound. By use of the maximum velocity (V) of the regurgitant jet, the systolic pressure gradient (delta P) between right ventricle and right atrium was calculated by the modified Bernoulli equation (delta P = 4V2). Adding the transtricuspid gradient to the mean right atrial pressure (estimated clinically from the jugular veins) gave predictions of right ventricular systolic pressure that correlated well with catheterization values (r = .93, SEE = 8 mm Hg). The tricuspid gradient method provides an accurate and widely applicable method for noninvasive estimation of elevated right ventricular systolic pressures.
Adolescent↗
Echocardiographic recognition and implications of ventricular hypertrophic trabeculations and aberrant bands.
The accuracy of two-dimensional echocardiography in the recognition of aberrant ventricular bands and pathologic trabeculations (hypertrophic, fibrotic, or both) was assessed in 35 patients who underwent cardiac transplantation and pathologic examination. At pathologic study the prevalence of specific intracavitary structures ranged from 28% to 43%. Left ventricular thrombi were found in 12 patients (34%) and right ventricular thrombi in three (9%). Echocardiography accurately defined left ventricular aberrant bands and left ventricular thickened or fibrotic trabeculations. Bands, trabeculations, and thrombi each showed characteristic echocardiographic patterns. In the right ventricle, these structures were recognized, but accurate discrimination among them was not possible by echocardiography. Aberrant bands and pathologic trabeculations mimicked or obscured fresh or organized thrombi in three patients on two-dimensional echocardiography. Left ventricular longitudinal bands and pathologic right ventricular trabeculations obscured the interventricular septal border in four patients; the presence of these abnormalities could lead to the erroneous diagnosis of asymmetric septal hypertrophy on M mode echocardiography. By expressing the accuracy of two-dimensional echocardiography in the recognition of left ventricular anomalous bands, our results support the feasibility of prospective studies to clarify their clinical significance.
Adolescent↗
An improved stochastic approach to rf amplitude analysis in ultrasonic cardiac tissue characterization.
We carried out a series of studies to improve the reproducibility of methods for ultrasonic myocardial tissue characterization using a stochastic approach to amplitude analysis of radiofrequency signals previously reported from our laboratory. Analysis of transducer scanner characteristics, data acquisition and processing, and data display from studies in tissue phantoms permit us to define some features of a parameter for expression of tissue character. The ratio of mean to standard deviation of the amplitude histogram from our system is explored as now implemented in our laboratory for reproducible measurements. The theoretical basis for understanding the utility of this method in defining tissue architecture and pathologic conditions requires further work.
Animals↗
Cardiac localization of transvascular bioptome using 2-dimensional echocardiography.
Two-dimensional (2-D) echocardiography was added to standard fluoroscopic localization of transvascular endomyocardial biopsy in 7 children with heart muscle disease whose ages were 6 months to 18 years. One left ventricular and 11 right ventricular biopsies were carried ot without complications using the fluoroscopic-echocardiographic technique. Two-dimensional echocardiographic monitoring has the advantages of reducing radiation exposure and providing anatomic information about intracardiac structures as well as bioptome localization. Lateral beam spread and reverberation artifacts represent potential problems with 2-D echocardiography, but they did not cause significant difficulties in this study.
Adolescent↗
In vivo ultrasonic tissue characterization of human intracardiac masses.
Interactions between an ultrasonic signal and cardiac tissue have been used to characterize the histologic state of myocardium in vitro. To assess the utility of in vivo ultrasonic tissue characterization, stochastic analysis was applied to the digitized echocardiographic signals from 15 patients with 2-dimensional echocardiograms suggesting intracardiac masses. Ten subjects with echocardiograms suggesting mural thrombi underwent subsequent surgery or necropsy, which confirmed thrombi in 6 and revealed no thrombi (designated artifact) in 4. Five other patients had intracardiac tumors. The amplitudes within the digitized ultrasonic signals were displayed as histograms, which were described by a parameter k that represented the degree to which each histogram departed from a totally random probability density function. In 5 of 6 thrombi, k = 0, but in all 4 artifacts, k greater than 0. The sixth thrombus had k = 0.5 due to the specular effect of the interface between the thrombus' 2 lobes. All 5 tumors had k greater than 0. Ultrasonic tissue characterization using a stochastic analysis of backscatter can be performed in vivo and helps differentiate thrombus from artifact and tumor in the heart.
Blood Coagulation↗
Rapid, semiautomated technique for estimating left ventricular volume.
A new system for rapidly quantitating left ventricular volume using two-dimensional echocardiography is tested. This system relies on a microprocessor built into a sector scanner that immediately calculates the length, area, and volume of the chamber being imaged using the mathematical model of an ellipsoid of revolution. The calculations are made after the observer superimposes a smooth calibrated ellipse outline on the endocardium imaged with the sector scanner. We report our experience with this system in 50 patients with a variety of cardiac disorders and compare the left ventricular volumes measured with those obtained using cineangiography, M-mode, and more detailed light pen tracing techniques. Correlations between volumes measured with the elliptical calipers and angiography were good (r = 0.820, SEE +/- 38.8 ml) (n = 100), but not as good as that between light pen tracing of the echo images and angiography (r = 0.847, SEE +/- 27.8 ml) (n = 22). M-mode correlated less well with angiography (r = 0.789; SEE +/- 42.1 ml) (n = 90). We conclude that the calibrated ellipse system is rapid and simple to use, while its accuracy matches previous studies using two-dimensional echocardiography to quantitate left ventricular volume.
Cardiovascular Diseases↗
Conduction disturbances related to the site and severity of mitral anular calcification: a 2-dimensional echocardiographic and electrocardiographic correlative study.
To investigate an apparent association of mitral anular calcium (MAC) and electrocardiographic abnormalities, the relation between location of 2-dimensional (2-D) echo-quantified MAC and conduction disturbances was studied in 140 patients with MAC (MAC group) and in 135 age- and sex-matched patients without MAC (control group). The MAC group was subclassified regarding site and severity of calcium in the mitral anulus. The site of MAC was defined as Type I, near the primary conduction system--MAC located in the medial segment and/or extending to the anterior mitral leaflet; and Type II--MAC located at the central and/or lateral segments away from the primary conduction system. The severity of MAC was graded on 2-D echocardiography as mild (localized within 1 segment) and moderate to severe (greater than 1 segment). Seven patients with MAC, and only 1 control subject, had pacemakers in place. Conduction disturbances were present in 44 (31%) of 140 patients with MAC, and in 37 (27%) of 135 control patients (difference not significant). But there were more conduction disturbances in patients with Type I MAC (53%) than in those with Type II MAC (26%) (p less than 0.01). Specifically, complete left bundle branch block and intraventricular conduction delay were more prevalent when MAC was near the conduction system. Conduction disturbances also were more prevalent in patients with Type I MAC than in the control group: intraventricular conduction delay (Type I, 12% versus control, 4%; p less than 0.05) and total conduction disturbances (53 versus 28%; p less than 0.01). These data suggest that moderate to severe degrees of MAC located near the conduction system are associated with conduction disturbances, especially intraventricular conduction delay.
Adult↗
Preoperative invasive testing in mitral stenosis: indications based on assessment of diagnostic yield.
The role of preoperative invasive testing in mitral stenosis was assessed in 82 patients undergoing cardiac catheterization for isolated mitral stenosis. The patients were diagnosed by physical examination and echocardiography and were considered for surgical treatment primarily to relieve dyspnea. They had no precordial murmur attributable to an aortic valvular lesion and had no history of chest pain. The presence of mitral stenosis was confirmed at catheterization in all patients. All 38 patients in New York Heart Association functional class III and 8 of 9 patients in class IV had hemodynamic confirmation of mitral disease warranting operation. Although a mitral gradient was present in all 35 patients in class II, operation was not recommended in 9 (26%) of 35 with normal or mildly elevated pulmonary arterial wedge pressure. Invasive testing did not increase preoperative knowledge of aortic. tricuspid, or pulmonary valvular lesions which required surgical treatment. Coronary arteriography was performed in 44 patients (54%) and identified 4 patients with luminal narrowing (greater than 70% diameter reduction) affecting 1 or 2 arteries. These results suggest that preoperative invasive testing in patients with mitral stenosis is unnecessary when symptoms are moderate to severe and clinical evidence of aortic valvular or coronary artery disease is absent. However, preoperative cardiac catheterization is indicated in patients with mild symptoms to avoid unnecessary or premature mitral valve operations.
Adult↗
Variability of digitized echocardiography: size, source, and means of reduction.
Digitization of M-mode echocardiograms provides useful information on left ventricular function, but its variability has been assessed rarely. Inter- and intraobserver (technical) variability of readers digitizing the same cardiac cycles, and variability between beats, days, and subjects (biologic) was determined. Technical variability was small for both standard dimensions (correlation coefficient r values 0.82 to 1.00) and rates of change (r values 0.70 to 0.98). Biologic variability was large with expected normal differences between 2 measurements (95% confidence limits) of 11 to 55% and 37 to 106% for standard dimensions and rates of change, respectively. By averaging measurements of 5 beats from each of 2 days, the expected normal differences are reduced to 6 to 32% and 23 to 63% for standard dimensions and rates of change. This study emphasizes the large biologic variability in rates of change of digitized left ventricular measurements. Normal variation between studies can be reduced and real physiologic or pathologic changes perceived best if many beats from more than 1 day are measured.
Adult↗
Standardized intracardiac measurements of two-dimensional echocardiography.
Thirty-five healthy adults were studied by two-dimensional echocardiography to attempt to standardize a simple method for measurement of intracardiac dimensions. Both ventricles and the atria and aorta were measured in five different views: parasternal long-axis, parasternal short-axis at the level of the aortic valve, the chordae tendineae and the papillary muscles and an apical four chamber view. The minor axis of each chamber was measured in all five views; the major axis in the apical four chamber view also was measured. All measurements are presented as a range of values (mean and 2 standard deviations about the mean); the mean value is given as well as the absolute range of values measured. Normalization according to body surface area is also presented. Data from these multiple views allow assessment of asymmetry of cardiac chambers in normal subjects. The mean minor axis dimension at end-diastole of the right ventricle in the parasternal long-axis view (1.9 to 3.8 cm) was 13.6% smaller than in the four chamber view (2.2 to 4.4 cm), whereas the minor axis dimension of the left ventricle in the parasternal long-axis view (3.5 to 6.0 cm) was only 1.1% larger than in the four chamber view (3.3 to 6.0 cm). Therefore, the right ventricular minor axis dimensions are not interchangeable. Reproducibility in 10 subjects for all dimensions showed a maximal variability of 4.8%. These values permit a standardized and expeditious method for measuring intracardiac dimensions by two-dimensional echocardiography.
Adolescent↗