Real-time intracardiac two-dimensional echocardiography: an experimental study of in vivo feasibility, imaging planes, and echocardiographic anatomy

The traditional transthoracic and transesophageal echocardiographic examination have proven to be useful imaging tools for studying cardiac morphology, pathology, and function. Recently, catheter-based ultrasound transducers have been available for intravascular ultrasonic imaging. We supposed that echocardiographic examination performed from within the heart itself can provide useful information about cardiac structure and function, especially in settings where transthoracic or transesophageal echocardiography may be technically difficult to perform or poorly tolerated by the patient. To explore this concept, we performed intracardiac echocardiography in vivo in 22 dogs using both 5-MHz and 20-MHz transducers. High-quality images were obtained in all animals. Using the higher frequency transducer, detailed images with only a limited depth of field were obtained. With the 5-MHz transducer, a comprehensive cardiac examination was feasible from within the right atrium and inferior vena cava. We were able to visualize the great vessels, all cardiac valves, and cardiac chambers in a multitude of imaging planes. Alterations in ventricular function were instantly recognized. Color Doppler capabilities allowed visualization of flow abnormalities as well. We conclude that intracardiac echocardiography is feasible and could be potentially useful in certain clinical situations. With further research and development, this technique may have an important clinical impact in cardiac therapy and diagnosis.     

Biplane transesophageal echocardiography utilizing transverse and sagittal imaging planes: technique, echo-anatomic correlations, and display approaches

The recent development of biplane transesophageal probes equipped with both transverse plane and sagittal plane imaging transducers allows a more complete examination of cardiac and aortic anatomy than is possible with conventional single plane transesophageal instruments. While the imaging planes used in transverse plane transesophageal imaging have been standardized, several different approaches have been suggested for the orientation and display of the newer sagittal plane images. An accepted display convention for the transverse and sagittal plane images would ease interpretation of the multiple complex images obtained during the biplane transesophageal examination. In this article, the different transverse plane and sagittal plane echocardiographic images that may be acquired during the biplane transesophageal examination are described and correlated with cardiac anatomy. A method for image display orientation is suggested that is most consistent with that previously used for the single plane transesophageal examination.     

Transesophageal biplane echocardiographic imaging: technique, planes, and clinical usefulness

The technique of examination, imaging planes, and the clinical utility of transesophageal biplane echocardiography are described.     

Reference Techniques for Left Ventricular Volume Measurement by Three-Dimensional Echocardiography: Determination of Precision, Accuracy, and Feasibility

The use of multiple in vitro reference methods to validate three-dimensional (3-D) echocardiographic techniques makes comparison difficult. In an attempt to establish a reference standard, we studied precision, accuracy, and feasibility of a true left ventricular (LV) volume measurement in six dog heart specimens using three techniques, called fluid, sheath, and cast. LV volumes ranged from 30 to 105 mL. Intraobserver variability was minimal in all combinations (1.26% to 2.8%) with a statistically insignificant tendency to higher values in the cast method. The cast method, however, exhibited significantly higher interobserver variability (5.78%) as compared to that ranging from 1.47% to 1.59% in the remaining two techniques. Regression analysis demonstrated high correlations among the three techniques assessed by 95% confidence limits and correlation coefficient (R² > 0.98, P < 0.01). Mean differences among the techniques (0.12 to 1.08 mL) were not significant. The fluid technique was easy to perform. The sheath technique required some practice. The cast method was sensitive to accurate preparation of a gelatin mixture. We conclude that the fluid and sheath techniques are precise, accurate, and feasible. We recommend their use as reference standards in laboratory LV volume measurement. Validation 3-D echocardiographic studies using either of these two techniques will be comparable. Although the accuracy of the cast technique is excellent, its lower precision makes it a second choice. It could be used in cases where an LV cavity cast is required and higher interobserver variability is acceptable.     

Pulsed-Wave Tissue Doppler and Color Tissue Doppler Echocardiography: Calibration with M-Mode, Agreement, and Reproducibility in a Clinical Setting

Background: Myocardial velocities can be measured with both pulsed-wave tissue Doppler (PWTD) and color tissue Doppler (CTD) echocardiography. We aimed to (A) to explore which of the two methods better approximates true tissue motion and (B) to examine the agreement and the reproducibility of the two methods in a routine clinical setting. Methods: For Study A, the displacements of 63 basal myocardial segments from 13 patients were examined with M-mode and compared with the velocity-time integral of PWTD and CTD velocities. For Study B, the basal lateral segments from 58 patients were examined with PWTD and CTD, and the peak myocardial velocities during systole (Sm), early diastole (Em), and late diastole (Am) were measured. Results: Study A: CTD-based measurements of displacement were 12% lower than M-mode measurements (95% CI: −18%; −6%). PWTD velocity-time integrals measured at the outer edge of the spectral band were 40% higher (33%; 46%) than M-mode measurements. Study B: PWTD measurements of myocardial velocity were systematically higher than CTD measurements: Sm 7.51 versus 5.54, difference 1.97 ± 1.41 cm/sec; Em 8.74 versus 6.86, difference 1.88 ± 1.70 cm/sec; Am 7.46 versus 5.17, difference 2.29 ± 1.82 cm/sec; P < 0.001 for all. Intraobserver coefficient of variation for Sm, Em, and Am were 6%, 12%, and 12% for PWTD, 14%, 13%, and 20% for CTD. Conclusions: CTD measures numerically smaller tissue velocities than PWTD, mostly due to an overestimation of true tissue motion by PWTD. The methods have good agreement and comparable reproducibility.     

New technology and methodologies for intraoperative,perioperative, and intraprocedural monitoring of surgical and catheter interventions for congenital heart disease

We review the new technology and methods available for support of intraoperative and intraprocedural imaging in the catheterization laboratory for surgical and interventional catheterization procedures in the treatment of congenital heart disease. The methods reviewed include miniaturized probes and new ways of using them perioperatively for cardiac imaging from transesophageal, substernal, and intracardiac imaging locations. The smaller and more versatile the probes, the better adapted they will be in providing methods to improve the outcomes in babies born with serious forms of congenital heart disease.     

Multiplane transesophageal echocardiography. Imaging planes, echocardiographic anatomy, and clinical experience with a prototype phased array OmniPlane probe

Multiplane transesophageal echocardiography is a new exciting development in echocardiography. We examined the methodology and echo-anatomic correlations of multiplane transesophageal echocardiography and its clinical applications in 100 patients. We used a 5-MHz phased array multiplane (OmniPlane) transesophageal probe. In this instrument, the transducer array can be steered through 180 degrees from any transducer location. This provides a vast assembly of imaging planes, allowing for detailed visualization of all dimensions of cardiac anatomy. This report presents our observations on the echocardiographic anatomy seen in various image planes and the unique clinical potential of multiplane transesophageal echocardiography in the diagnostic assessment of cardiovascular disorders. This technique appears to provide incremental diagnostic information that enhances the interpretative ability. Less esophageal probe manipulation is required with consequent decrease in patient discomfort. We conclude that multiplane transesophageal echocardiography enhances the versatility of transesophageal examination and offers many new avenues for developments such as three-dimensional echocardiography.     

Multiplane Transthoracic Echocardiography: Image Orientation, Anatomic Correlation, and Clinical Experience with a Prototype Phased Array Multiplane Surface Probe

Multiplane transthoracic echocardiography provides numerous sequential images by rotation of the transducer imaging array through 180° with the surface probe at a fixed site. We explored the potential of this new technique with a 3.7/5-MHz prototype multiplane transthoracic probe. Echoanatomic correlations were first examined in ten explanted hearts. The transducer was then applied in 30 normal humans at transthoracic acoustic windows to determine the imaging planes available. Use of this probe in 76 patients with various cardiac disorders indicated that this probe eases the procedure of transthoracic echocardiographic examination, provides incremental information for improved delineation and understanding of cardiac pathology, and yields many novel insights to echocardiographic interpretation. Multiplane transthoracic echocardiography appears to expand the versatility of transthoracic two-dimensional echocardiography.     

Transoesophageal echocardiography in heart disease—old technologies, new tricks

Cardiac ultrasound and upper gastrointestinal endoscopy are relatively old technologies. With the introduction of new ultrasound probes and by incorporating ultrasound technology into conventional endoscopes, ‘new tricks’ in cardiac imaging were discovered. Posterior structures of the heart are now able to be imaged clearly by the ultrasound probe from the oesophagus. Consequently, better resolution of cardiac anatomy allows more accurate diagnosis of cardiac pathologies which is not possible using conventional transthoracic (TT) approach. Over a period of two years, 1200 cases of transoesophageal echocardiography (TOE) were undertaken in our institution. The major indications were diseases of the aorta (10%), source of cardioembolism (28%), assessment of native and prosthetic valve function (20%), suspected endocarditis and its complication (17%), pre and post percutaneous transluminal mitral valvotomy (PTMV [13%], congenital heart disease (2%) and others (10%). The greatest impact with TOE is in the diagnosis of aortic dissection and transection, TOE is superior to conventional TT approach in detecting potential source of embolism, valvular vegetations and its complication, native and prosthetic valve dysfunction and LA thrombus prior to PTMV. Observations by TOE such as spontaneous echo contrast (SEC) in the left atrium open new challenges for further research in its role in the pathogenesis of LA thrombus and its association with cardioembolic event. Other areas of interest include; reclassification of distal aortic dissection and the use of TOE in intra-operative work.     

Determination of left ventricular volume, ejection fraction, and myocardial mass by real-time three-dimensional echocardiography

Reconstructed three-dimensional (3-D) echocardiography is an accurate and reproducible method of assessing left ventricular (LV) functions. However, it has limitations for clinical study due to the requirement of complex computer and echocardiographic analysis systems, electrocardiographic/respiratory gating, and prolonged imaging times. Real-time 3-D echocardiography has a major advantage of conveniently visualizing the entire cardiac anatomy in three dimensions and of potentially accurately quantifying LV volumes, ejection fractions, and myocardial mass in patients even in the presence of an LV aneurysm. Although the image quality of the current real-time 3-D echocardiographic methods is not optimal, its widespread clinical application is possible because of the convenient and fast image acquisition. We review real-time 3-D echocardiographic image acquisition and quantitative analysis for the evaluation of LV function and LV mass.     

Evaluation of cardiac involvement in hypereosinophilic syndrome: complementary roles of transthoracic, transesophageal, and contrast echocardiography

Hypereosinophilic syndrome is a rare but important systemic disease with multiple clinical presentations. Approximately 40% of these cases have cardiac involvement. Echocardiography is the most easily available and versatile imaging modality in assessing cardiac involvement in this disease process. As described and reviewed in this case, it may be the first imaging modality to raise suspicion of this disease entity. Hence, clinicians interpreting echocardiograms and caring for patients need to be aware of the manifestations and complementary roles of various echo techniques in delineating cardiac involvement. Furthermore, the importance of a thorough history and laboratory review prior to echocardiography may provide valuable clues which may otherwise be missed.     

Left ventricular volume measurement with echocardiography: a comparison of left ventricular opacification, three-dimensional echocardiography, or both with magnetic resonance imaging

Aims: Both contrast enhanced (CE) two-dimensional echocardiography(2DE) and three-dimensional echocardiography (3DE) have beenproposed as techniques to improve the accuracy of left ventricular(LV) volume measurements. We sought to examine the accuracyof non-contrast (NC) and CE-2DE and 3DE for calculation of LVvolumes and ejection fraction (EF), relative to cardiac magneticresonance imaging (MRI). Methods and results: We studied 50 patients (46 men, age 63 ± 10 year) withpast myocardial infarction who underwent echocardiographic assessmentof LV volume and function. All patients sequentially underwentNC-2DE followed by NC-3DE. CE-2DE and CE-3DE were acquired duringcontrast infusion. Resting echocardiographic image quality wasevaluated on the basis of NC-2DE. The mean LV end-diastolicvolume (LVEDV) of the group by MRI was 207 ± 79 mL andwas underestimated by 2DE (125 ± 54 mL, P = 0.005), andless by CE-2DE (172 ± 58 mL, P = 0.02) or 3DE (177 ±64 mL, P = 0.08), but EDV was comparable by CE-3DE (196 ±69 mL, P = 0.16). Limits of agreement with MRI were similarfor NC-3DE and CE-2DE, with the best results for CE-3D. Resultswere similar for calculation of LVESV. Patients were categorizedinto groups of EF (35, 35–50, >50%) by MRI. NC-2DEdemonstrated a 68% agreement (kappa 0.45, P = 0.001), CE-2DEa 62% agreement (kappa 0.20, P = 136), NC-3DE a 74% agreement(kappa 0.39, P = 0.005) and CE-3DE an 80% agreement (kappa 0.56,P < 0.001). Conclusion: CE-2DE is analogous to NC-3DE in accurate categorization ofLV function. However, CE-3DE is feasible and superior to otherNC- and CE-techniques in patients with previous infarction.     

Echocardiography,endocarditis, and clinical information bias

Although clinical information provided to the interpreter of imaging tests may improve disease detection, it may also bias the interpreter towards certain diagnoses, increasing the chance of false positives. To determine the possibility of this bias, the authors studied patients who were referred for echocardiography with a clinical suspicion of endocarditis. Hospital charts from a two-year period were reviewed to determine clinical data available to the echocardiographer, echocardiogram results, and the final diagnosis. Four clinical features, when present at the time of echocardiography, were associated with increased numbers of false-positive results. Test specificity was 97% (34/35) for patients without any of these features, but dropped to 80% (16/20) when two or more features were present. The authors conclude that clinical information may bias echocardiogram interpretations such that both test specificity and the posttest probability of disease may be overestimated when tests are used in clinical practice. Received from the General Medicine Unit, Department of Medicine, Strong Memorial Hospital and University of Rochester School of Medicine and Dentistry, Rochester, New York. Supported in part by the Henry J. Kaiser Family Foundation.     

Panoramic transesophageal echocardiography. Clinical application of real-time, wide-angle, transesophageal two-dimensional echocardiography and color flow imaging

Panoramic transesophageal echocardiography is a new development in transesophageal echocardiography (TEE) technology, which yields a wide-angle imaging field for real-time two-dimensional and color flow imaging. We report our early experience in patients with the use of an annular-array TEE probe that provides a wide, 270 degrees angle imaging field for two-dimensional echocardiographic imaging. The field of view can, however, be narrowed to 15 degrees . The field of view for color flow imaging can be varied from 180 degrees to 10 degrees . Pulsed-Doppler recordings of flow velocity are also possible. This TEE system provides a panoramic vision of cardiac and paracardiac structures from the esophagus and stomach. Besides cardiovascular structures, other thoracic and upper abdominal organs can be visualized. The wide field of view allows a better comprehension of the cardiac anatomy and its relationship with adjacent structures. The initial experience suggests that this method, besides providing the usually required diagnostic information, may have a number of additional applications. Its clinical potential and directions for future developments are reviewed.     

Positional localization: three-dimensional transthoracic echocardiographic techniques for the measurement of cardiac mass, volume, and function

An accurate and reproducible determination of cardiac volume and mass is important for the selection and timing of therapeutic interventions. Quantitative three-dimensional echocardiography has evolved to provide these measurements with the use of a noninvasive, readily available, and inexpensive technique. We introduce and review the principle of positional localization as well as the clinical application of this technique for the measurement of cardiac volume and mass.     

Échocardiographie transœsophagienne pour guider la ponction transseptale. Guide pratique,astuces, particularités,pièges

Transesophageal echocardiography is very useful to guide transseptal puncture for left atrial ablation procedures. This paper is a practical guide for the ultrasonographer who seeks to meet the expectations of the electrophysiologist, but also for young EP's in order to improve their understanding of the echocardiographical views and to ameliorate the communication between the two specialists. The tips and tricks of all the steps of the exam are presented.     

Full performance of modern echocardiography within the heart: in-vivo feasibility study with a new intracardiac, phased-array ultrasound-tipped catheter.

BACKGROUND: Intracardiac echocardiography with full performance of high-resolution two-dimensional-, M-mode-, colour, pulsed and continuous wave Doppler and Doppler tissue imaging has not been previously demonstrated. AIMS: This first European in-vivo study was designed to determine the utility and feasibility of a new ultrasound-tipped catheter for intravascular and intracardiac echocardiography. METHODS: The miniaturized, multi-modal, multiple-frequency (5-10MHz) transducer tipped 10Fr (3.3mm) catheter was tested in five anaesthetized mongrel dogs linked to a standard echocardiographic platform. The catheter was introduced through an 11 Fr femoral venous sheath into the inferior vena cava and right heart chambers and the pulmonary artery under limited fluoroscopic and catheter ultrasound guidance. RESULTS: Abdominal and thoracic aorta as well as their branches, both ventricles and atrias with their appendices, all valves, pulmonary arteries and all veins could be visualized with excellent quality. All Doppler signals and the determined haemodynamics, global and regional wall motion and Doppler tissue imaging were of high diagnostic quality. Coronary flow reserve could also be determined. CONCLUSIONS: Intracardiac echocardiography is feasible and potentially useful for assessing functional and morphological disorders, and probably for the guidance of interventional procedures as well as monitoring of cardiac function. A new window to the heart has been opened.     

Heart,COVID-19, and echocardiography

Although clinical manifestations of coronavirus disease of 2019 (COVID-19) mainly consist of respiratory symptoms, a severe cardiovascular damage may occur. Moreover, previous studies reported a correlation of cardiovascular metabolic diseases with severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), and actually, many COVID-19 patients show comorbidities (systemic hypertension, cardio-cerebrovascular disease, and diabetes) and have a raised risk of death. The purpose of this review is to focus the cardiovascular effects of 2019-nCoV on the base of the most recent specific literature and previous learnings from SARS and MERS and analyze the potential role of echocardiography during the current critical period and short- and long-term follow-up.