Biplane transesophageal echocardiography: an anatomic-ultrasonic-clinical correlative study

The development of echocardiography in China: the pioneering role of Xin-fang Wang

I cannot discuss the history of the development of echocardiography in China without describing the pioneering role of Xin-fang Wang (王新房) from Wuhan, China, who is the "father of modern echocardiography."(1) Although Inge Edler from Sweden(2-5) and Harvey Feigenbaum from the United States(6) were also oftentimes referred to as the fathers of echocardiography, both Edler(7) and Feigenbaum(8) recognized that the Chinese used cardiac ultrasonography in the very early years (Figure 1).

Incidence and clinical significance of interatrial shunting in patients with atrial septal aneurysm detected by contrast transesophageal echocardiography

The prevalence of atrial septal aneurysm (ASA) in a general referral population of patients was investigated by use of transthoracic (TTE) and transesophageal echocardiographies (TEE). Contrast TEE was performed to detect interatrial shunting in patients with ASA. In this population, the prevalence of ASA as determined by TTE was 0.47% (24/5,079), and 0.78% (40/5,079) by TEE. Of these 40 patients 16 (40%) were judged to be normal by TTE. Of the forty patients who were positive for ASA, 50% demonstrated interatrial shunting (atrial septal defects, 10; patent foramen ovale, 10). The authors concluded that TEE is of significant value in detecting the presence of ASA and associated cardiac abnormalities. Contrast TEE further enhances the detection of interatrial shunting in patients with ASA.

Intraoperative transesophageal echocardiography during liver transplantation

OBJECTIVE

To investigate the safety, value, and impact of transesophageal echocardiography during liver transplantation.

DESIGN

Retrospective.

SETTING

University teaching hospital.

PARTICIPANTS AND INTERVENTIONS

The medical records of 346 patients and the videotapes of 100 intraoperative transesophageal echocardiography examinations were reviewed.

MEASUREMENTS AND MAIN RESULTS

Transesophageal echocardiography was indicated for intraoperative monitoring in 62 patients, 41 of whom had pertinent findings, and for diagnostic purposes in 38 patients, 14 of whom had the expected diagnosis verified. Thirty-one patients had no intraoperative findings. Information that would not have been detected intraoperatively by other means included intracardiac defects, the potential for transpulmonary air passage, valvular regurgitation, the presence or absence of ventricular dysfunction, and embolization occurring at allograft reperfusion. Unanticipated findings during the initial transesophageal echocardiography examination as well as evaluation of intraoperative events resulted in a major impact on patient management in 11% of patients. Preoperatively, 64 patients had a prothrombin time greater than 14 seconds; 56 had a platelet count less than 100,000/mm3; and 23 had esophageal varices, 7 of whom had not had variceal sclerotherapy. Two patients had a complication possibly caused by transesophageal echocardiography (sinus bradycardia and upper gastrointestinal bleeding). No patient experienced documented variceal hemorrhage, esophageal or gastric perforation, and/or oropharyngeal trauma.

CONCLUSIONS

It appears that transesophageal echocardiography can be performed safely in patients undergoing liver transplantation, is efficacious in rapidly disclosing new information and monitoring during periods of hemodynamic instability, and may have a significant impact on intraoperative patient management during liver transplantation.

Intraoperative multiplane vs biplane transesophageal echocardiography for the assessment of cardiac surgery

This study was undertaken to test whether multiplane transesophageal echocardiography (TEE) offers advantages in comparison with biplane TEE in the intraoperative monitoring during cardiac surgery. A diagnostic multiplane TEE was performed in 400 patients in the immediate preoperative and postoperative periods. We systematically acquired cardiac images from the gastric fundus, lower esophagus, and upper esophagus; complete views of the descending aorta were also recorded. Usefulness of the different views in providing essential additional clinical information compared with exclusive transverse (0 to 20 degrees) and longitudinal (70 to 110 degrees) planes of the biplane TTE was assessed assuming that with manipulation of a biplane probe, a 20 degrees are could be added to the conventional horizontal and vertical planes. A high success rate of each view was demonstrated; anatomy and pathologic condition were best visualized in oblique planes. The method proved to be particularly useful in the preoperative and postoperative phases of aortic dissection (27 cases), aortic (65 cases) and mitral (35 cases) valve replacement, mitral valve repair (38 cases), left ventricular aneurysmectomy (25 cases), bleeding from proximal suture of an aortic heterograft (2 cases), and positioning of left ventricular hemopump (2 cases). Additional regional wall motion abnormalities of the right (four cases) and left ventricle (six cases) not appreciated in 0 to 20 degrees or 70 to 110 degrees planes were detected. Multiplane TEE is a useful clinical tool during intraoperative monitoring of cardiac surgery. Most structures of the heart and great vessels lie on oblique planes, while other views are optimized with the aid of slight angle corrections. This method improves the evaluation of anatomy and pathologic condition of the heart and great vessels, of native and prosthetic valves, and of left and right ventricular function.

Transesophageal echocardiographically facilitated early cardioversion from atrial fibrillation using short-term anticoagulation: final results of a prospective 4.5-year study

OBJECTIVES

We sought to validate the safety of transesophageal echocardiographically guided early cardioversion in conjunction with short-term anticoagulation as a strategy for guiding early cardioversion in hospitalized patients with atrial fibrillation.

BACKGROUND

Because atrial thrombi are poorly seen by conventional imaging techniques, several weeks of prophylactic anticoagulation is routinely prescribed before cardioversion. Transesophageal echocardiography is a superior test for identifying atrial thrombi; preliminary feasibility studies have supported its use to guide early cardioversion for patients in whom no thrombus is observed, but safety has not been validated in any large series.

METHODS

All patients admitted to hospital with atrial fibrillation during a 4.5-year period were screened. The inclusion criterion was a clinical duration of atrial fibrillation > 2 days or of unknown duration. Patients received anticoagulation with heparin/warfarin and underwent conventional transthoracic echocardiography followed by transesophageal study. Patients in whom transesophageal echocardiography revealed no atrial thrombus underwent pharmacologic or electrical cardioversion followed by warfarin therapy for 1 month. Cardioversion was deferred in patients with evidence of atrial thrombi, and they received prolonged warfarin treatment.

RESULTS

Two hundred thirty-three patients (86% of those eligible) agreed to participate, and 230 underwent transesophageal echocardiography. Transesophageal echocardiography identified 40 atrial thrombi (left atrium 34, right atrium 6) in 34 patients (15%). One hundred eighty-six (95%) of 196 patients without thrombi had successful cardioversion to sinus rhythm, all without prolonged anticoagulation, and none (0%, 95% confidence interval 0% to 1.6%) experienced a clinical thromboembolic event. Eighteen patients with atrial thrombi underwent uneventful cardioversion after prolonged anticoagulation.

CONCLUSIONS

Compared with smaller series that have shown only feasibility, this large prospective and consecutive study of patients undergoing transesophageal echocardiographically facilitated early cardioversion in conjunction with short-term anticoagulation validates the safety of this strategy. This treatment algorithm has a safety profile similar to conventional therapy and minimizes both the period of anticoagulation and the overall duration of atrial fibrillation.

Study on three dimensional reconstruction of transesophageal echocardiographic images

Using biplane transesophageal echocardiography and the concept of three dimensional transthoracic echocardiography, we performed three dimensional reconstruction of transesophageal images of various clinicopathologic cases, including atrial septal defect, mitral stenosis, mitral valve prolapse and pulmonary stenosis. The hardware equipment and image processing flow chart of three dimensional reconstruction of transesophageal echocardiographic images are described. Our present study indicates that three dimensional reconstruction of transesophageal echocardiographic images could display multi-regional three dimensional structures of heart and great vessels, including superior vena cava, ascending aorta, right ventricular outflow tract, pulmonary artery and left heart, with clear, visual and stereoscopic imaging. The regional structures could be displayed at different levels of stereo-anatomic-sections and in different orientations of rotating stereo-images, which could provide accurate three dimensional anatomical information for cardiac stereo-morphological study and definition of spatial location and size of cardiac abnormalities.

Three-dimensional transesophageal echocardiography in the diagnosis of mitral valve prolapse

Because the anulus of the mitral valve is nonplanar in systole, false-positive diagnosis of mitral valve prolapse may result from two-dimensional transthoracic echocardiography. Because of the superior image quality of TEE, we used the three-dimensional TEE technique to evaluate the mitral valve in both normal subjects and patients with mitral valve prolapse and with ruptured chordae tendineae. After a conventional TEE examination, sequential images of longitudinal views were obtained by probe rotation. The images at 5-degree intervals were stored in machine cine memory loop; the special temporal images were selected with ECG gating and videorecorded. During the examination, 6 to 8 images of the left heart were recorded for later off-line, three-dimensional reconstruction. A total of 42 subjects were studied: 32 normal, 9 with mitral valve prolapse, and 1 with ruptured chordae tendineae. In normal subjects, three-dimensional TEE showed nonplanarity of the entire mitral valve, which assumes a saddle shape. In mitral valve prolapse, either the anterior or posterior leaflet protruded into the left atrium like a spoon; when both leaflets are involved, they prolapse like two spoons. The anterior and posterior leaflets coapted poorly, and there was a seam between them. In ruptured chordae tendineae the tip of the mitral leaflet protruded during systole into the left atrium far from the coaptation point and was perpendicular to the body of the mitral valve and parallel to the anterior and posterior walls of the left atrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical application of three-dimensional transesophageal echocardiography

Three-dimensional transesophageal echocardiography is a new and evolving cardiac imaging technique. We reported our experiences of its clinical applications in 59 patients. A series of special temporal longitudinal views were selected by the frame grabber. Then the computer connected each digitized endocardial surface of the longitudinal views according to their spatial position and reconstructed the three-dimensional, cardiac shaded picture with gray scale. The three-dimensional transesophageal echocardiographic images were divided into three areas. The right area was right anterior to the esophagus and included such structures as the superior vena cava, right atrium, interatrial septum, and left atrium; the size, shape, and location of an atrial septal defect could be clearly shown. In the middle area the origin and the course of the two great arteries could be visualized, thus facilitating the diagnosis of transposition of the great arteries; in patients with obstruction of the right ventricular outflow tract, the circular ridgelike narrowing in the right ventricle was clearly visualized. In the left area the contour and size of the left ventricle and left atrium and the shape and point of coaptation of the mitral valve could be demonstrated; in patients with mitral valve prolapse, part of either leaflet protruded into the left atrium and appeared as a spoonlike depression in the mitral valve. Other entities subjected to three-dimensional transesophageal echocardiographic reconstruction included cor triatriatum, left atrial myxoma, aneurysm of sinus of Valsalva, dissecting aortic aneurysm, mitral stenosis, mitral regurgitation, and mitral valve prolapse.(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of biplane transesophageal echocardiography in neonates, infants and children with congenital heart disease

A study was performed to assess the feasibility, additional diagnostic value and potential applications of biplane transesophageal echocardiography in neonates, infants and children. One hundred thirty-two consecutive studies were attempted in 111 anesthetized children with congenital heart disease. Longitudinal and transverse planes were compared using 3 methods: (1) separate 7 mm longitudinal and transverse pediatric transducers used sequentially; (2) an experimental 9 x 8 mm biplane pediatric transducer; and (3) a standard adult biplane transducer (12 x 9 or 13 x 9 mm). In all but 1 patient, a probe could be inserted. The longitudinal plane provided superior visualization of both the right and left ventricular outflow tracts, the interatrial septum, the main pulmonary artery, the ascending aorta and the right coronary artery. In 18 patients (16%), the longitudinal plane provided completely new diagnostic information that was not obtained with combined transthoracic and transverse plane transesophageal echocardiography. However, the transverse plane was mandatory for demonstration of the 4-chamber view, short-axis cross sections through the great arteries, the distal right pulmonary artery and bifurcation of the left coronary artery. The longitudinal plane is complementary to the transverse plane, but cannot substitute for it.

Cardioversion from atrial fibrillation without prolonged anticoagulation with use of transesophageal echocardiography to exclude the presence of atrial thrombi

BACKGROUND

Because atrial thrombi are poorly detected by conventional noninvasive techniques such as transthoracic echocardiography, patients with prolonged atrial fibrillation usually receive several weeks of oral anticoagulation therapy before cardioversion is attempted. We wondered whether transesophageal echocardiography, an accurate method of detecting atrial thrombi, would allow early cardioversion to be performed safely if no thrombi were identified.

METHODS

A total of 669 consecutive patients admitted with the diagnosis of atrial fibrillation were screened. Patients were excluded if they were receiving long-term anticoagulation, if the duration of atrial fibrillation was two days or less, if they were not candidates for cardioversion, or if transesophageal echocardiography was contraindicated. Of 119 qualifying patients, 94 agreed to participate; the average duration of atrial fibrillation was 4.5 weeks. Participating patients underwent transthoracic echocardiography and transesophageal echocardiography followed by cardioversion if no thrombi were seen. Short-term anticoagulation with heparin was used in 80 patients before cardioversion, and 60 patients received warfarin for one month after cardioversion.

RESULTS

Fourteen atrial thrombi were identified in 12 patients (13 percent), and 12 of the 14 thrombi were visualized only on transesophageal echocardiography. Cardioversion was deferred in all 12 patients. Two of these 12 patients died suddenly; 4 of the 10 surviving patients underwent uneventful cardioversion after prolonged oral anticoagulation. Seventy-eight of the 82 patients without thrombi underwent successful cardioversion to sinus rhythm (47 by means of antiarrhythmic drugs and 31 by electrical cardioversion), all without long-term oral anticoagulation. None of these patients (95 percent confidence interval, 0 to 4.6 percent) had an embolic event.

CONCLUSIONS

In patients with atrial fibrillation of unknown or prolonged duration who are not receiving long-term anticoagulation, atrial thrombi are detected by transesophageal echocardiography in only a small minority (13 percent in our study). Our preliminary data suggest that if transesophageal echocardiography excludes the presence of thrombi, early cardioversion can be performed safely without the need for prolonged oral anticoagulation before the procedure.

Pitfalls in the echo-Doppler assessment of diastolic dysfunction

The Doppler echocardiographic assessment of diastolic function is an essential part of the evaluation of heart failure, pericardial diseases, restrictive and infiltrative cardiomyopathies, and many other conditions. However, the echocardiographic evaluation of diastolic function has several limitations. The sonographer and physician must understand the technical factors, the effects of physiological and pathophysiological conditions, and the dynamics of pseudonormalization, all of which affect the evaluation. This article will review the most recent data essential for the proper performance and interpretation of a transthoracic or transesophageal Doppler echocardiographic examination of diastolic function.