Support vector analysis of color-Doppler images: a new approach for estimating indices of left ventricular function

Reliable noninvasive estimators of global left ventricular (LV) chamber function remain unavailable. We have previously demonstrated a potential relationship between color-Doppler M-mode (CDMM) images and two basic indices of LV function: peak-systolic elastance (Emax) and the time-constant of LV relaxation (tau). Thus, we hypothesized that these two indices could be estimated noninvasively by adequate postprocessing of CDMM recordings. A semiparametric regression (SR) version of support vector machine (SVM) is here proposed for building a blind model, capable of analyzing CDMM images automatically, as well as complementary clinical information. Simultaneous invasive and Doppler tracings were obtained in nine mini-pigs in a high-fidelity experimental setup. The model was developed using a test and validation leave-one-out design. Reasonably acceptable prediction accuracy was obtained for both Emax (intraclass correlation coefficient Ric, = 0.81) and tau (Ric, = 0.61). For the first time, a quantitative, noninvasive estimation of cardiovascular indices is addressed by processing Doppler-echocardiography recordings using a learning-from-samples method.

Cardiac motion analysis from ultrasound sequences using nonrigid registration: validation against Doppler tissue velocity

Early detection of cardiac motion abnormalities is one of the main goals of quantitative cardiac image processing. This article presents a new method to compute the 2-D myocardial motion parameters from gray-scale 2-D echocardiographic sequences, making special emphasis on the validation of the proposed technique in comparison with Doppler tissue imaging. Myocardial motion is computed using a frame-to-frame nonrigid registration technique on the whole sequence. The key feature of our method is the use of an analytical representation of the myocardial displacement based on a semilocal parametric model of the deformation using Bsplines. Myocardial motion analysis is performed to obtain displacement, velocity and strain parameters. Robustness and speed are achieved by introducing a multiresolution optimization strategy. To validate the method, velocity measurements in three different regions-of-interest in the septum have been compared with those obtained with Doppler tissue velocity in healthy and pathologic subjects. Regression and Bland-Altman analysis show very good agreement between the two different approaches, with the great advantage that the new method overcomes the angle-dependency limitations of the Doppler techniques, providing both longitudinal and radial measurements.

Effects of angiotensin converting enzyme inhibitors in hypertensive patients with aortic valve stenosis: a drug withdrawal study

OBJECTIVE

To determine the effects of angiotensin converting enzyme (ACE) inhibitors in hypertensive patients with aortic valve stenosis (AS).

DESIGN

Observational, drug withdrawal, single blinded study, with randomisation of the order of tests.

SETTING

Hypertension and asymptomatic AS.

PATIENTS AND INTERVENTIONS

20 patients (aged 73 (9) years, valve area 0.7 (0.3) cm2, left ventricular ejection fraction > or = 45%) were enrolled. Each patient underwent two sets of tests (with and without taking the drug), each of which included clinical evaluation, Doppler echocardiogram, and symptom limited exercise echocardiography.

MAIN OUTCOME MEASURES

Functional and haemodynamic variables while taking and not taking ACE inhibitors.

RESULTS

Drug intervention induced no change in patients' subjective functional class. While taking ACE inhibitors, patients had a lower systolic blood pressure (140 (18) mm Hg with ACE inhibitors v 159 (12) mm Hg without ACE inhibitors, p = 0.02), a higher mean pressure gradient (34 (15) mm Hg v 28 (18) mm Hg, p = 0.037), and a higher left ventricular stroke work loss (19 (6)% v 14 (10)%, p = 0.009). Other baseline functional and haemodynamic parameters were unmodified. Five patients had an abnormal blood pressure response during one of the exercise tests (two patients while taking the drug and three patients while not taking the drug). When taking ACE inhibitors, patients had a higher stroke volume at peak stress (59 (11) ml v 54 (25) ml, p = 0.046). All other stress variables remained constant.

CONCLUSIONS

In AS, the afterload relief caused by ACE inhibitors is blunted by a parallel increase in the pressure gradient. However, ACE inhibitors favourably affect stress haemodynamic function in most hypertensive patients with AS and should not be discontinued.

Two years' activity of the Veterinary Toxicology Attention Service of Lugo, Spain

The Veterinary Toxicology Attention Service was created at the beginning of 2001 as the first on-line toxicology service for veterinarians and animal owners in Spain. In the present study, data about the general functioning of the Service and the toxicological analysis and consultations performed are summarized. Canine-related cases constituted the main call group and veterinary practitioners represented half of the consultations. Coordination between all veterinary toxicology services in Spain and the rest of the European Union should improve this service.

Portable spectral Doppler echocardiographic device: overcoming limitations

BACKGROUND

There is evidence that new portable echocardiographic devices are useful in evaluating heart anatomy and function, but a lack of Doppler modes has up to now been an important limitation in obtaining haemodynamic data.

OBJECTIVES

To report the Doppler capabilities of a new hand held echocardiographic device.

DESIGN

Blinded comparison of two types of echocardiography machine.

SETTING

Tertiary care centre.

PATIENTS

98 consecutive patients were randomly imaged with the hand held device, with a standard platform as reference.

OUTCOME MEASURES

Pulsed wave transmitral Doppler inflow tract velocities, deceleration time, and continuous wave Doppler measurements of aortic ejection and tricuspid regurgitation peak velocities were recorded.

RESULTS

There was excellent agreement between the hand held device and standard echocardiography for the evaluation of diastolic E and A waves, E/A ratio, and deceleration time with pulsed wave Doppler (intraclass correlation coefficients of 0.97, 0.93, 0.90, and 0.78, respectively). In addition, good agreement was found between continuous wave Doppler measurements of aortic ejection and tricuspid regurgitation velocities (intraclass correlation coefficients of 0.96 and 0.80). However, there was a significant difference between patients with tricuspid regurgitation measured with the hand held device (25.5%) and by standard echocardiography (65.3%), resulting in misdiagnosis of eight patients with pronounced pulmonary hypertension.

CONCLUSIONS

New hand held devices with Doppler capabilities overcome previous limitations in evaluating haemodynamic variables. With colour Doppler they are now suitable for the complete evaluation of valvar disease and diastolic function. However, important limitations remain in the evaluation of pulmonary pressures.

Use of contrast echocardiography in the diagnosis of subacute myocardial rupture after myocardial infarction

Myocardial rupture is an uncommon and catastrophic complication after acute myocardial infarction. It can present in an acute form or in a subacute form, with slower hemorrhage and thrombus formation at the site of rupture. These patients can survive several hours or days before the diagnosis is confirmed and the myocardial ruptured repaired. Two-dimensional Doppler echocardiography is very useful in the diagnosis of this complication, but the number of false-positive diagnoses is high, even in the presence of a large amount of pericardial effusion. In these patients, administration of a contrast agent can be useful to demonstrate active bleeding into the pericardium. We report a case of subacute myocardial rupture for which contrast echocardiography was useful in demonstrating the presence of persistent hemorrhage into the pericardium. To reduce the number of false-positive diagnoses, contrast echocardiography should be considered in patients with possible subacute myocardial rupture.

Spatio-temporal mapping of intracardiac pressure gradients. A solution to Euler's equation from digital postprocessing of color Doppler M-mode echocardiograms

Doppler assessment of intracardiac pressure gradients using the simplified Bernoulli equation is inaccurate in the absence of a restricted orifice. The purpose of this study is to develop a new general method to map instantaneous pressure gradients inside the heart using Doppler echocardiography. Color Doppler M-mode recordings are digitally postprocessed with a software algorithm that decodes flow velocity and fits a bivariate spatio-temporal tensor-product smoothing spline. Temporal and spatial accelerations are then calculated by analytical derivation of the fitted velocity data, allowing solution of both inertial and convective terms of Euler's equation. A database of 39 transmitral inflow and transaortic outflow color Doppler M-mode recordings from 20 patients with a number of cardiac conditions was analysed, along with matched pulsed-wave spectral recordings. A close agreement was observed between the spectral and postprocessed color Doppler velocity values (error = 0.8 +/- 11.7 cm/s), validating the data decoding and fitting process. Spatio-temporal pressure-gradient maps were obtained from all studies, allowing visualisation of instantaneous pressure gradients from the atrium to the apex during left ventricular filling, and from the apex to the outflow tract during ejection. Instantaneous pressure differences between localised intracardiac sample points closely matched previously published catheterization findings, both in magnitude and waveform shape. Our method shows that intracardiac instantaneous pressure gradients can be analysed noninvasively using color Doppler M-mode echocardiography combined with image postprocessing methods.

[Meaning of clinical and electrical positivity in the myocardial perfusion scintigraphy during the administration of dipyridamole]

BACKGROUND AND OBJECTIVES

Administration of dipyridamole produces angina and ST depression in 20%-30% and 6%-34% of patients, respectively. This study aimed to evaluate the clinical implications of the presentation of angina and/or ST depression during the administration of dipyridamole in the study of coronary heart disease by myocardial perfusion SPECT (MPS).

METHODS

The study population is constituted by 593 consecutive patients without left branch block or ventricular pacemaker rhythm who were referred to our service to undergo MPS with dipyridamole. A SPECT was performed after the administration of 99mTc-tetrosfosmine and drug stimulation with dipyridamole (0.142 mg/kg/min for 4 minutes). A coronariography was performed in 338 patients (57%). The frequency of clinical and electrical positivity and their relationship with the MPS and the coronariography were studied.

RESULTS

The rate of angina and ST depression was 32% (n = 190) and 10% (n = 58), respectively. Myocardial perfusion defects were observed in 465 patients (78%), and signs of scintigraphic ischemia in 311 (52%). The patients with ST depression presented a higher frequency of perfusion defects (93% vs 76%, p = 0.0012) and scintigraphic ischemia (89% vs 49%, p < 0.0001). In addition, perfusion defects in more than one territory were observed in these patients in a higher percentage (53% vs 34%, p = 0.0036). Among the patients who underwent cardiac catheterization, those who had a ST depression had a greater extension of coronary heart disease (1.8 +/- 1.2 vs 1.3 +/- 1.0 diseased vessels, respectively. p = 0.0100) and a higher frequency of multivessel disease (61% vs 43%, p = 0.0380). Those patients who had clinical positivity showed a scintigraphic ischemia more frequently (66% vs 47%, p < 0.0001), however no statistically significant differences were observed between the presence of patients with perfusion defects or in the extension of these defects as well as in the number of diseased vessels in the coronariographic study.

CONCLUSIONS

During the administration of dipyridamole, the ST depression is associated with more frequent scintigraphic ischemia, larger extension of perfusion defects and more diseased vessels. The appearance of angina is associated with scintigraphic ischemia, but it is not necessarily associated with the extension of perfusion defects or greater number of diseased vessels.

Doppler tissue imaging

This paper try to give a general overview of the main areas of DTI clinical application, its main technical limitations, new directions still under investigation and some potential future developments of this emerging imaging technique. In this review article we pretend to discuss the main aspects of the new DTI method, its present "state of the art" and future perspectives of scientific and technical development.

Dynamic three dimensional evaluation of intracardiac flow

Three-dimensional color Doppler is a new technique that provides three dimensional images of intracardiac flow jets. Despite the different measurement methods available, noninvasive quantification of valve regulation is still controversial in some cases. It is also sometimes difficult to appreciate the spatial extension of the jet. Visualisation of regurgitant flows in three dimensions shows its complex shape, origin, direction and spatial distribution, and correlates accurately with regurgitant volume and regurgitant fraction by different methods (angiography, two-dimensional Doppler). Unnoticed its in the two-dimensional image have been detected with the three-dimensional image and additional qualitative information to the two dimensional image has been provided by this new technique in a high percentage of patients.

Quantification of myocardial perfusion using contrast echocardiography: methodological basis of image postprocessing

Intravenous contrast agents have provided the opportunity to clinically assess myocardial perfusion using ultrasound. In perfusion echocardiography, obtaining maximal diagnostic information requires the use of digital image postprocessing techniques, since subjective visual interpretation can be frequently inaccurate. Prior research using other intravascular tracers such as radioactive microspheres provides the theoretical basis for perfusion analysis that can be readily implemented to contrast echocardiography. Aspects of digital videodensitometric quantification, fitting to gamma-variable mathematical wash-in/wash-out functions and parameter analysis have been well validated for other tracers and have demonstrated excellent applicability in contrast echo. Currently available scanner technologies provide with a number of image-acquisition modalities, from standard continuous to intermittent-triggered images that require specific postprocessing algorithms. The present paper reviews the basis of temporal and spatial contrast postprocessing. The issues of image registration, background subtraction, videointensity measurement and mathematical function fitting are also discussed. This theoretical background should be helpful to understand the general aspects of currently available and future systems of perfusion densitometric systems.

Predictors of left atrial spontaneous echo contrast and thrombi in patients with mitral stenosis and atrial fibrillation

The purpose of this study was to investigate the independent factors associated with the presence of left atrial (LA) spontaneous echo contrast (SEC) and thromboembolic events in patients with mitral stenosis (MS) in chronic atrial fibrillation (AF). Factors independently associated with LASEC, thrombi, and embolic events have been mainly investigated in patients with nonvalvular AF or inhomogeneous populations with rheumatic heart disease. Transesophageal and transthoracic echo studies were performed in 129 patients with MS in chronic AF. Previous embolic events were documented in 45 patients, 20 of them within 6 months, and 65 patients were receiving long-term anticoagulation. The intensity of LASEC and mitral regurgitation, the presence of thrombi and active LA appendage flow (peak velocities > or = 20 cm/s), and LA volume as well as other conventional echo-Doppler determinations were investigated in every patient. The prevalences of significant LASEC (degrees 3+ and 4+), thrombus, active LA appendage flow, and significant mitral regurgitation (>2+) were: 52% (67 patients), 29.5% (38 patients), 32% (41 patients), and 36% (47 patients), respectively. Multivariate analysis showed that decreasing mitral regurgitation severity, absence of active LA appendage flow, and mitral valve area were the independent correlates of LASEC (odds ratio [OR] 3.7, 5.4, and 0.17, respectively; all p <0.02). Active LA appendage flow and anticoagulant therapy were associated negatively, whereas the severity of LASEC was associated positively with the finding of LA thrombus (OR 9.6, 3.9, and 1.6, respectively; all p <0.05). The intensity of LASEC and previous anticoagulant therapy (OR 1.74 and 4.5, respectively; p <0.005) were the independent covariates of thrombi and/or recent embolic events. In conclusion, the severity of mitral regurgitation and lack of active LA appendage flow were, respectively, the strongest independent correlates of significant LASEC and thrombus in patients with MS in chronic AF. LASEC remains the cardiac factor most strongly associated with thrombus and/or recent embolic events in these patients.

[Results of myocardial scintigraphy with 99mTc-tetrofosmin and dipyridamole administration in patients diagnosed of microvascular angina]

The objective of the study was to evaluate the results of the myocardial scintigraphy with 99mTc-tetrofosmin (Tc-Tf) and pharmacological stimulation with dipyridamole in patients diagnosed of microvascular angina. The study population is made up of 50 patients discharged with the diagnosis of microvascular angina who had undergone Tc-Tf-dipyridamole. Clinical and electrical positivity appeared in 40% and 12% of the patients, respectively. Myocardial perfusion defects were found in 35 patients (70%), and were reversible in 21 (60%), fixed in 11 (21%), and combined in 3 (9%). Abnormalities were inferior, anteroseptal and lateral in 21, 18, and 2 patients, respectively. Patients with a positive exercise treadmill test, compared with those with a negative one, had more frequent perfusion abnormalities (91% vs 50%, p = 0.0327) and myocardial ischemia (64% vs 20%, p = 0.392). Women, in comparison with men, had angina (56% vs 22%, p = 0.013), and anteroseptal perfusion abnormalities (26% vs 4%, p = 0.028) more frequently. On the contrary, men had inferior perfusion abnormalities more frequently (57% vs 30%, p = 0.057). Thus, Tc-Tf-dipyridamole shows perfusion abnormalities in 70% of patients with microvascular angina (91% in patients with a positive exercise treadmill test). Scintigraphic pattern may be partially conditioned by gender in these patients.

Frequency of left ventricular free-wall rupture in patients with acute myocardial infarction treated with primary angioplasty

A total of 590 patients with myocardial infarction treated with primary angioplasty were studied, to assess the incidence and related factors of free-wall rupture in patients with acute myocardial infarction when treated with primary angioplasty. The incidence of free-wall rupture was 2.2% (13 patients); this incidence was higher in patients >65 years old, women, nonsmokers, as well as in those with anterior location and an initial TIMI grade 0 flow, but it was similar in patients with a successful or unsuccessful angiographic result.

Flow dynamics of stenotic aortic valves assessed by signal processing of Doppler spectrograms

Clinical assessment of aortic stenosis (AS) is sometimes challenging, because all hemodynamic indexes of severity are modified by flow rate. However, the mechanisms underlying flow dependence remain controversial. Analysis of instantaneous flow dynamics has provided crucial information in a number of cardiovascular disorders and may add new insight into this phenomenon. This study was designed to analyze in vivo the effects of flow interventions on instantaneous valvular dynamics of stenotic valves. For this purpose, a custom algorithm for signal processing of Doppler spectrograms was developed and validated against a control population. Digital Doppler recordings at the aortic valve and left ventricular outflow tract were obtained in 15 patients with AS, at baseline and during low-dose dobutamine infusion; 10 normal subjects were studied as controls. Spectrograms were processed by signal averaging, time alignment, modal-velocity enhancement, envelope tracing, and numerical interpolation. Instantaneous relative aortic valve area (rAVA) was obtained by the continuity equation and plotted against normalized ejection time. Curves were classified as either type A (rapid, early-systolic opening) or type B (slow, end-systolic opening). Curves from controls closely matched prior knowledge of normal valve dynamics, but curves from patients were clearly different: all controls except 2 (80%) had type A, whereas all patients except 3 (80%) had a type B pattern (p = 0.03). Dobutamine infusion in patients increased and slightly anticipated peak rAVA by accelerating valve opening. Despite similar values of area and pressure difference, type B dynamics were associated with lower blood pressure (p = 0.01) and worse long-term outcome (>3 years) than type A flow dynamics (p = 0.02). Signal processing of Doppler spectrograms allows a comprehensive assessment of aortic flow dynamics. Differences in timing of valve aperture and in maximal leaflet excursion account for flow-mediated changes in valve area, suggesting complementary effects of inertia and elasticity on the kinetics of stenotic aortic valves. Flow-dynamic analysis provides novel clinical information regarding physiology of AS unavailable to conventional indexes.

Voltammetric study and determination of buprenorphine in pharmaceuticals

The oxidation of buprenorphine on a carbon paste electrode has been studied using voltammetric techniques under both semi-infinite linear diffusion and hydrodynamic conditions. By applying a simple electrode pretreatment a good reproducibility of the current signal is obtained (R.S.D. = 0.85%, n = 6 for a 1.0 x 10(-5) M buprenorphine concentration). The limit of detection was found to be 2.0 x 10(-7) M. The voltammetric method developed for the determination of buprenorphine in pharmaceutical preparations was examined for its applicability to liquid and solid preparations.

[The Doppler color detection of internal mammary artery anastomoses and a functional assessment of their patency]

BACKGROUND

Left internal mammary artery coronary graft patency is usually evaluated invasively by cardiac catheterization. The objective of this study was to assess the ability of a high-frequency transthoracic Doppler echocardiographic system in the evaluation of patency and flow velocities changes in left internal mammary artery.

METHODS

Twenty-two patients (63 +/- 9 years, 17 male) who had previously undergone left internal mammary artery to left anterior descending artery were evaluated by transthoracic echocardiography, with an Acuson Sequoia C256 equipment (Acuson, Mountain view, USA), placing the transducer (5 MHz) in the second-third left intercostal space. Left internal mammary artery flow was considered to be found in the presence of one systolic/diastolic biphasic blood flow. Dipiridamol 0.5 mg/kg was administered in absence of contraindications in order to evaluate the flow reserve.

RESULTS

In 16 patients (73%), a biphasic systolic-diastolic flow was visualized. Peak velocity of systolic and diastolic waves was 38 +/- 13 and 37 +/- 15 cm/s, respectively. Eleven patients received i.v. dipiridamol 0.5 mg/kg. After dipiridamol, systolic and diastolic velocities rose from 32 +/- 8 to 43 +/- 14 cm/s (p = 0.0429) and from 25 +/- 8 to 50 +/- 17 cm/s (p = 0.0002), respectively (an increasing of 33 +/- 22% and 103 +/- 46% over the baseline, respectively).

CONCLUSION

This descriptive study shows that a non-invasive functional evaluation of left internal mammary artery grafts by a transthoracic approach with a high-frequency echocardiographic equipment is possible.

Regional diastolic function in ischaemic heart disease using pulsed wave Doppler tissue imaging

AIMS

The aim of this study was to determine the utility of pulsed wave Doppler tissue imaging in the evaluation of regional left ventricular diastolic function in patients with ischaemic heart disease.

METHODS AND RESULTS

In 30 normal subjects and 43 patients with ischaemic heart disease, Doppler tissue imaging was performed in each of the 16 segments of the myocardium. The following diastolic pulsed wave Doppler tissue imaging parameters were obtained for each segment: (1) regional early diastolic peak velocity (regional e wave cm.s-1); (2) regional late diastolic peak velocity (regional a wave cm.s-1); (3) regional diastolic e/a velocity ratio; and (4) the regional isovolumic relaxation time, defined as the time interval from the second heart sound to the onset of the diastolic E wave. In patients with ischaemic heart disease, each of these parameters was evaluated and compared in ischaemic and normally perfused segments, based on the presence or absence of obstructive lesions of the supplying coronary artery. In patients with coronary artery disease, several differences were observed between diseased and normal wall segments: the mean segmental peak early diastolic velocity (e wave) was reduced (mean +/- SD: 6.4 +/- 2.1 cm.s-1 vs 8.5 +/- 2.8 cm.s-1; P < 0.01); the e/a diastolic velocity ratio was decreased (0.95 +/- 0.3 vs 1.5 +/- 0.6, respectively; P < 0.01) and the regional isovolumic relaxation time was prolonged (104 +/- 36.7 ms vs 69.6 +/- 30 ms; P < 0.01. No differences were observed in any of these parameters between the normally perfused segments of ischaemic patients and normal subjects. Patients with a normal transmitral diastolic Doppler inflow pattern had a mean of 3.7 +/- 2.7 myocardial segments with a local e/a pulsed wave Doppler tissue imaging velocity ratio < 1, fewer than those with an inverted diastolic transmitral Doppler inflow pattern (10.3 +/- 3 segments; P < 0.001). Overall sensitivity and specificity for an inverted local e/a ratio and a local isovolumetric relaxation time > or = 85 ms were of 62% and 72% and 69% and 80%, respectively.

CONCLUSION

Regional diastolic wall motion is impaired at baseline in ischaemic myocardial segments, even when systolic contraction is preserved. Pulsed wave Doppler tissue imaging is a useful non-invasive technique which allows the assessment of regional diastolic performance and dynamics of the left ventricular myocardium. Further studies are required to define this role in the evaluation of coronary heart disease.

Dissection of the aortic sinus of Valsalva complicating coronary catheterization: cause, mechanism, evolution, and management

We have rarely observed the appearance of a dissection of the aortic sinus of Valsalva during catheterizations of the related coronary artery. The aim of this study is to describe the cause, mechanism, and evolution of this complication, which have implications for the management of the patient. According to our experience (one case out of 12,546 diagnostic and three cases out of 4,970 angioplasty procedures performed during the last 6 years), the dissection of the sinus of Valsalva always results from the retrograde extension of a dissection of the right coronary artery. It usually remains localized, but it may quickly involve the entire aorta. Contrast injections and balloon inflations promote its propagation, so these procedures should be avoided if possible. Instead of angiography, transesophageal echocardiogram is a safe and accurate method for studying its extension and as a follow-up method. The sinus of Valsalva dissections that remain localized during catheterization tend to spontaneously resolve in the first month.

Role of transesophageal echocardiography in the assessment of patients with blunt chest trauma: correlation of echocardiographic findings with the electrocardiogram and creatine kinase monoclonal antibody measurements

OBJECTIVES

This study was designed to evaluate the usefulness of transesophogeal echocardiography (TEE) for detecting cardiac damage after blunt chest trauma (BCT).

BACKGROUND

Multiple methods have been used to detect cardiac damage after a BCT, but none has been demonstrated to be sensitive, specific, and feasible enough.

METHODS

This multicenter prospective trial was designed to evaluate the usefulness of TEE in the assessment of patients with BCT and to compare the TEE findings with those provided by the electrocardiogram (ECG) and cardiac isoenzymes assay. One hundred seventeen consecutive patients with a significant BCT were enrolled. A TEE was performed in each patient. Serial ECGs and plasma profiles of creatine kinase (CK) and CK-monoclonal antibody (MB) were obtained.

RESULTS

Sixty-six (56%) patients had pathologic findings in the TEE attributed to the BCT (group A). In the remaining 51 (44%) patients the TEE was normal (group B). An abnormal ECG was more frequent in group A (59% vs 24%; p < 0.001), and the serum CK-MB peak level was also higher in group A (174 +/- 30 U/L vs 93 +/- 21 U/L; p = 0.05). Relative to pathologic TEE findings, the sensitivity and specificity of an abnormal ECG were 59% and 73% and of high CK-MB with CK-MB/CK > 5% were 64% and 52%, respectively.

CONCLUSIONS

We conclude that TEE can be routinely and safely performed for diagnosing cardiac injuries after a BCT and plays an important role in the evaluation and treatment of these patients. EGG and CK-MB assay are not good methods for detecting cardiac damage in this setting.

[Changes in therapeutic attitude based on transesophageal echocardiography in cardiac surgery]

Transesophageal echocardiography is a monitoring system that is changing the practice of cardiovascular anesthesia and surgery by providing real time images of cardiovascular anatomy and pathophysiology. Our hospital's anesthesiology and postoperative intensive care departments, in particular the cardiac anesthesia team, initiated a joint project in June 1993 with the echocardiography laboratory team to incorporate this surgical monitoring system. Here we report the wealth of information we obtained and describe the possibility of modifying a therapeutic approach based on the images visualized, even when conventional monitoring gives contradictory information. Two illustrative case reports are included.

Clinical and echocardiographic findings in HIV patients with pericardial effusion

BACKGROUND AND OBJECTIVES

Pericardial effusion (PE) is frequently found in patients infected with the human immunodeficiency virus (HIV), but its clinical significance remains unclear. Our purpose was to study the manifestations of HIV-infected patients with PE and the coexistence of these manifestations with other echocardiographic abnormalities, compared with patients without PE.

METHODS

We reviewed 141 HIV-infected patients in whom echocardiographic study was performed. We studied their epidemiological, clinical, hematological, immunological, electrocardiographic (ECG) and echocardiographic characteristics and their in-hospital outcome.

RESULTS

Patients with PE (n = 55), compared with those without PE (n = 86), were more often clinical stage C and immunological stage 3, had left-ventricular dysfunction and right-ventricular dilatation more frequently, and had been diagnosed as HIV-positive for a longer time. Seven patients with moderate to severe PE developed cardiac tamponade. Compared with patients with small PE (n = 34), those with moderate to large PE (n = 21), had pericardial rub, ECG repolarization abnormalities consistent with pericarditis, immunological stage 3, left-ventricular dysfunction and right-ventricular dilatation more frequently. In 3 patients, cardiac tamponade disappeared after anti-tuberculous therapy; in 3 cases, pericardial drainage was performed (anti-tuberculous therapy was not attempted); 1 patient with cardiac tamponade was not drainaged because he was a terminal patient with an extensive lymphoma.

CONCLUSIONS

PE in HIV-infected patients is associated with (1) advanced stages of infection, and (2) left-ventricular dysfunction and right-ventricular dilatation; (3) presence of pericardial rub and ECG alterations consistent with pericarditis suggests the existence of moderate to large PE.

Effects of dobutamine on Doppler echocardiographic indexes of aortic stenosis

OBJECTIVES

This study sought to assess the diagnostic implications of the flow dependence of Doppler echocardiographic indexes of aortic valve stenosis.

BACKGROUND

Although valve area has been shown to change with alterations in flow rate, the diagnostic consequences of this phenomenon remain unknown. Valve resistance has been suggested as a more stable index for evaluating aortic stenosis.

METHODS

A low dose dobutamine protocol was performed in 35 patients with aortic stenosis. Hemodynamic indexes were obtained by Doppler echocardiography at baseline and at each dobutamine dose.

RESULTS

As a result of the shortening of the systolic ejection period, flow increased from (mean +/- SD) 164 +/- 48 to 229 +/- 102 ml/s (p < 0.0001). At peak flow, valve area increased by 28% (from 0.5 +/- 0.2 to 0.6 +/- 0.3 cm2, p < 0.0001), whereas valve resistance decreased by 4% (from 498 +/- 252 to 459 +/- 222 dynes.s.cm-5, p = 0.04). This observed change in resistance was smaller than that for valve area (p < 0.01). The flow dependence of valve area varied among individual patients (p < 0.0001). Multivariate analysis identified calcific degenerative etiology (beta 0.29, p = 0.002), left ventricular velocity of fiber shortening (beta 0.22, p = 0.01), baseline flow (beta -0.28, p = 0.04) and amount of flow increased induced by dobutamine (beta 0.90, p < 0.0001) as factors related to valve area flow dependence.

CONCLUSIONS

Although all Doppler echocardiographic indexes of aortic stenosis are affected by flow, valve resistance is more stable than valve area under dobutamine-induced hemodynamic changes. Baseline valve area may be unreliable in patients with calcific degenerative aortic stenosis and low output states.

Prediction of right ventricular ejection fraction by Doppler determination of right systolic time intervals

OBJECTIVES

This study was designed to evaluate the right ventricular function by means of the determination of right ventricular systolic time intervals measured in pulmonary artery flow detected by Doppler.

BACKGROUND

Left ventricular systolic time intervals have been used to evaluate left ventricular performance. There is, however, no information as to whether right ventricular systolic time intervals may be useful in the evaluation of right ventricular function.

METHODS

Simultaneous measurements of right ventricular ejection fraction and Doppler determination of right systolic time intervals were made in four pigs in 47 different hemodynamic conditions that permit the modification of the right ventricular ejection fraction from 15% to 68%. The preejection time, the ratio of right preejection time to right ventricular ejection time, with and without correction by the heart rate, were correlated simultaneously to invasively determined right ventricular ejection fraction and other hemodynamic parameters, measured with a modified pulmonary artery catheter with a rapidly responding thermistor.

RESULTS

There was a significant linear correlation between Doppler determination of right systolic time intervals and right ventricular ejection fraction. A similar correlation was found for preejection time (r = .80, p < .0001) and the ratio of right preejection time to right ventricular ejection time with correction by the heart rate (r = .83, p < .0001). When we used a preejection time > 70 msec as a criterion to detect a ejection fraction < 40% we found a sensitivity of 89% and specificity of 88%. A preejection time > 80 msec, as criterion of more severe ventricular disfunction (ejection fraction < 30%), displayed a sensitivity of 76% and specificity of 100%.

CONCLUSION

These results show that right ventricular systolic time intervals determined by Doppler study correlate significantly with the right ventricular ejection fraction. In view of its simplicity and its accuracy in the prediction of right ventricular ejection fraction, this method may provide useful non-invasive alternative in the prediction of right ventricular ejection fraction.

[The echocardiographic assessment of wall regurgitant jets in prosthetic mitral valves: the superiority of multiplanar transesophageal sections over standard sections]

OBJECTIVES

The purpose of this study was to determine whether multiplanar (MP) transesophageal echocardiographic views were superior to standard views (ST), in the evaluation of mitral prosthesis regurgitation (MR), particularly in presence of wall regurgitant jets.

METHODS

We studied all mitral prostheses (n = 43) in which pathological mitral regurgitation had been detected by multiplanar TEE between January 1993 and March 1994. Regurgitant prostheses were classified in two groups according to the presence of wall regurgitant jets and maximum turbulent color flow areas (Amax.) were measured on standard (0 and 90 degrees) and MP (0 to 180 degrees) views.

RESULTS

The Amax. detected on ST views were 5.80 +/- 4.60 cm2 and on MP 7.42 +/- 5.13 cm2. Student's test was used to compare both areas and significant differences were found: 1.61 cm2; 95% confidence interval from 0.94 to 2.28 cm2; p = 0.000025. The sample was divided in two groups, A (n = 33): with wall jets and B (n = 10): without wall jets. The Amax. for group A was 5.64 +/- 4.30 cm2 in ST views, and 7.51 +/- 5.12 cm2 in MP. The difference was statistically significant: 1.86 cm2, 95% c.i. from 1.04 to 2.68 cm2; p = 0.00009. Differences for group B were also statistically significant: 0.68 cm2; p = 0.0172. MP views detected a bigger regurgitant area in 26 of the 43 cases (60%). The difference between ST and MP views was significantly bigger for group A than for group B: mean 1.18 cm2; p = 0.0176. MP views detected a severer degree of MR, classified as mild moderate and severe according to the color flow area, than ST views in 8 patients. All of them had wall regurgitant jets. Three had been considered normal on ST views.

CONCLUSION

We conclude that MP transesophageal views are significantly superior to ST in the assessment of regurgitant prosthetic mitral valves, particularly in presence of wall regurgitant jets. Our data strongly suggest that multiplanar TEE is the procedure of choice in the assessment of wall regurgitant mitral prostheses.

[The usefulness of transesophageal echocardiography in general intensive care units]

BACKGROUND AND OBJECTIVES

It's well known the utility of transesophageal echocardiography in the evaluation of cardiological patients that are critically ill. However, there is less experience about this usefulness in non-cardiological critically ill patients.

METHODS

To assess the utility and safety of the method we analyzed 51 correlative studies of patients admitted to our general Intensive Care Unit. Forty-seven patients (92%) were on mechanical ventilation and in 24 patients (47%) continuous assessment of the hemodynamic variables were available.

RESULTS

The most frequent diagnoses on admission were sepsis (23.5%) and shock status (17.6%). The indications were: suspicion of endocarditis (15 patients), hemodynamic instability (11 cases), cardiac source of embolus (10), suspicion of cardiac tamponade (4), suspicion of aortic dissection (4) and other causes in 7. The study confirmed the clinical suspicion in 31 cases (60.8%), excluded it in 15 (29.4%) and established a new, non-suspected, diagnosis in 5 patients (9.8%). There were major diagnostic changes in 16 patients (31.6%) and minor changes in 17 (33.3%) comparing the results of the transesophageal and transthoracic approaches. It was also assessed the influence of the result on the clinical management of the patient: in 32 cases (62.8%) there were a significant change in the treatment; in 5 patients (9.8%) cardiac surgery was prompted by echocardiography. Only in 3 patients hypertensive reactions and tachycardia were detected, without posterior consequences.

CONCLUSIONS

Transesophageal echocardiography can be safely performed and has a definite role in the diagnosis (showing sometimes non-suspected abnormalities) and management of non-cardiological critically ill patients.

[Perforation of the mitral valve: transesophageal echocardiographic diagnosis in 3 cases]

We submit 3 cases of perforation of the mitral valve leaflet as a consequence of infectious endocarditis. In the first of this cases, perforation was the result of the impact of the regurgitant jet of an aortic insufficiency affected by bacterial endocarditis of the anterior mitral leaflet in a young female presenting various congenital malformations. Both the transthoracic and transesophageal echocardiography showed that the regurgitant jet affected the area where the lesions were later detected. In the other 2 cases the perforation appeared in valves previously affected by endocarditis. In these cases, only the transesophageal echocardiography showed the lesions. Surgery was performed in all 3 cases with satisfactory results, confirming the echocardiographical findings. We wish to emphasize the role of transesophageal echocardiography in the diagnosis of this rare process that may be the primary effect of the destructive action of the endocarditis, or a secondary effect, on dissemination by means of affected valves, on previously unaffected valvular leaflets.

[The progression of a postinfarct interventricular communication: an echocardiographic follow-up]

An 80-year-old female patient presented rupture of the interventricular septum as complication of acute anteroseptal myocardial infarction. Serial echocardiographic studies documented progressive increase in size of the apical defect over 16 hours. This observation highlights a potential hazard if surgical repair is deferred to "stabilize" hemodynamically the patient before the intervention.

[Usefulness of carotid sinus massage for Doppler quantification of mitral stenosis in sinus rhythm]

The quantification of mitral stenosis by pressure half-time method may be difficult in sinus rhythm with short deceleration slopes. To evaluate the usefulness of carotid sinus massage (CSM) for measuring mitral valve area by pressure half-time, 80 consecutive patients with mitral stenosis in sinus rhythm underwent a echo-Doppler study at basal heart rate and during right CSM. In both situations we measured: heart rate, mitral area by pressure half-time and E-F interval (time from E peak velocity to onset of atrial contraction). In 38 consecutive patients we also determined the mitral area by planimetry. The study group was divided into patients with basal E-F interval < or = 150 ms and a HR > or = 75 bpm (group A, 28 patients [35%]) and those with a basal E-F interval > 150 ms who showed a heart rate < 75 bpm (group B, 52 patients). In the group A, the values obtained at basal heart rate vs after CSM were: heart rate, 86 +/- 9 vs 61.6 +/- 10.5 lpm; E-F interval, 109 +/- 33 vs 372 +/- 136 ms; mitral area, 1.88 +/- 0.5 vs 1.23 +/- 0.29 cm2 (p < 0.001). In the group B, these values were: 69.7 +/- 6.6 vs 53 +/- 11 bpm, 253 +/- 60 vs 510 +/- 212 ms y 1.34 +/- 0.3 vs 1.18 +/- 0.32 cm2, respectively (p < 0.01). Mean differences in Doppler mitral areas between both situations for groups A and B were: 0.63 +/- 0.3 cm2 and 0.17 +/- 0.1 cm2, respectively (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

[Transesophageal echocardiography in mitral prosthesis dysfunction: usefulness and limitations in the evaluation of mitral insufficiency]

This study was performed to test the usefulness of transesophageal echocardiography in the diagnosis and assessment of pathological mitral regurgitation in patients with mitral valve prostheses. Doppler color flow imaging by transesophageal echocardiography was compared to the transthoracic echocardiography and angiographic and surgical assessment. We analyzed the influence of the spatial configuration of the jet on the semiquantitative assessment of mitral regurgitation. We studied 71 patients with prostheses in mitral position which were submitted for transesophageal echocardiography examination. 51 of these patients were found to have a pathological prosthetic regurgitation that was confirmed in 21 cases by left ventriculography and in 4 during cardiac surgery. Transesophageal echocardiography Doppler color flow imaging identified a regurgitant jet in 31 patients (60.7%). There was complete agreement with the quantitative assessment of regurgitation by angiography or surgery in 36% of the cases. All patients with prosthetic insufficiency observed by angiography or during cardiac surgery were confirmed by transesophageal echocardiography. Complete agreement in grade of severity by transthoracic echocardiography was found in 84% of cases. There was a difference in grade of severity of mitral regurgitation in only 4 patients. Regurgitant jets were classified by transesophageal echocardiography color Doppler in two groups: free jets and impinging wall jets. 21 cases presented a free jet and 31 excentrically directed impinging wall jet of mitral regurgitation. There was complete agreement with hemodynamic assessment of severity in all patients with regurgitant free jets (11/11). In presence of jet wall there was understimation of mitral regurgitation in 28.5% (4/13).(ABSTRACT TRUNCATED AT 250 WORDS)

[Meaning of mosaic color area in mitral regurgitation. Echocardiographic transesophageal study]

OBJECTIVE

The purpose of our study was to analyse the meaning of total and mosaic color Doppler area of the mitral regurgitation jet, in terms of the degree of mitral regurgitation severity.

PATIENTS

In and out patients referred to the Echocardiographic Laboratory of Gregorio Marañon General Hospital, Madrid.

SETTING

Transesophageal echocardiographic prospective study

MATERIAL AND METHODS

By pulsed and color Doppler transesophageal approach we studied 94 consecutive patients with mitral regurgitation diagnosis. We divided the entire population in three groups according to the degree of transthoracic mitral regurgitation severity and mitral regurgitation color area index (Groups I, II and III). In each patient we systematically measured the regurgitant maximal area (AT) and of the aliasing color area, as well as maximal peak velocity (VIS) and area (AIS) of the reversed pulmonary venous pulsed Doppler flow obtained at the level of the left upper pulmonary vein.

RESULTS

For the group I, color Doppler AT was 411 +/- 315 mm2 and AN was 204 +/- 123 mm2 (R = 0.25), pulmonary venous pulsed Doppler VIS was 4 +/- 8 cm/sec (R = NS for AT and 0.79 for AN) and AIS was 9 +/- 6 mm2 (R = NS for AT and 0.82 for AN). In the group II, color Doppler AT was 802 +/- 447 mm2, AN was 671 +/- 307 mm2 (R = 0.42). the pulmonary venous pulsed Doppler VIS was 22 +/- 12 cm/sec (R = NS for AT and 0.66 for AN). In the group III we obtained an AT value of 1174 +/- 462 mm2 and an AN value of 1092 +/- 417 mm2 (R = 0.62). In this group the pulmonary venous pulsed Doppler VIS was 50 +/- 13 cm/sec (R = 0.57 for AT and 0.76 for AN) and the correspondent AIS was 671 +/- 570 mm2 (R = 0.38 for AT and 0.91 for AN).

CONCLUSIONS

Mosaic transesophageal echocardiographic color Doppler area of mitral regurgitant jets has a direct relationship with the reversal criteria of pulsed Doppler pulmonary venous flow. This relationship is greater than the total color Doppler area of the same regurgitant jet. The mosaic color Doppler area of mitral regurgitant jets is a more correct estimation of the systolic variation of left atrial pressure, when compared with the total color area of mitral regurgitation.