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Biomedical subjects

A R Weintraub

Publications and source records attributed to A R Weintraub.

11 recordsLinked to original sources
PubMed1996

Excision of a pulmonary valve abscess in a 61-year-old woman with single ventricle.

A 61-year-old woman with levo-transposition of the great arteries, double-inlet single left ventricle, and valvar and subvalvar pulmonary stenosis presented with a large pulmonary valve vegetation unresponsive to antibiotic therapy. The diagnostic evaluation and the surgical management are discussed. At operation the pulmonary valve was excised and an abscess cavity was obliterated with a pericardial patch. She is currently doing well 3 years after the operation.

Abscess↗
PubMed1994

Intravascular ultrasound imaging in acute aortic dissection.

OBJECTIVES: This study was performed to determine the potential of intravascular ultrasound in the detection and delineation of aortic dissection. BACKGROUND: Intravascular ultrasound is a new technique capable of displaying real-time cross-sectional images of arterial vasculature. Its clinical use has been explored mostly in coronary and peripheral arterial circulation. METHODS: Intravascular ultrasound imaging of the aorta was performed using a 20-MHz ultrasound catheter in 28 patients with suspected aortic dissection. All patients underwent contrast angiography; 7 had computed tomography; and 22 had transesophageal echocardiography. RESULTS: Imaging of the aorta from the root level to its bifurcation was performed in all patients in an average of 10 min. No complications occurred. Dissection was present in 23 patients and absent in 5. In the patients without dissection, intravascular ultrasound revealed normal aortic anatomy. In all 23 patients with dissection, intravascular ultrasound demonstrated the intimal flap and true and false lumena. The longitudinal and circumferential extent of aortic dissection, contents of the false lumen, involvement of branch vessels and the presence of intramural hematoma in the aortic wall could also be identified. In cases where aortography could not define the distal extent of the dissection, intravascular ultrasound did. CONCLUSIONS: Our experience in this series of patients with aortic dissection indicates that intravascular ultrasound could be valuable in the identification and categorization of aortic dissection and in the description of associated pathologic changes that may be clinically important. It can be performed rapidly and safely and could serve as an alternative or adjunct diagnostic procedure in patients with aortic dissection.

Acute Disease↗
PubMed1993

Intracardiac echocardiography in humans using a small-sized (6F), low frequency (12.5 MHz) ultrasound catheter. Methods, imaging planes and clinical experience.

OBJECTIVES: This study was designed to determine the clinical utility and feasibility of using 12.5-MHz ultrasound catheters for intracardiac echocardiography. BACKGROUND: Intracardiac echocardiography is a potentially useful technique of cardiac imaging and monitoring in certain settings. The feasibility of intracardiac echocardiography using 20-MHz ultrasound catheters in patients has been demonstrated. High resolution images of normal cardiac structures as well as cardiac abnormalities have been obtained. However, imaging has been limited by the shallow depth of field inherent in high frequency ultrasound imaging. METHODS: Intracardiac echocardiography with 12.5-MHz catheters was performed in eight mongrel dogs and 92 patients. Catheters were introduced percutaneously in 80 patients studied in the catheterization laboratory and directly into the heart in 12 patients in the operating room. Right heart imaging was performed in 68 patients and arterial and left heart imaging in 35 patients. RESULTS: When these catheters were introduced into the venous system, the right atrium, tricuspid valve, right ventricle, pulmonary valve and pulmonary artery were visualized. Pericardial effusion, intracardiac masses and atrial septal defects were correctly identified. The left ventricle, left atrium, mitral valve, aortic valve, aorta and coronary arteries could be imaged from the arterial circulation. Diseases identified included valvular aortic stenosis, subvalvular aortic stenosis and Kawasaki disease. Average imaging time was 10 min. No complications occurred as a result of intracardiac echocardiography. CONCLUSIONS: Intracardiac echocardiography with 12.5-MHz ultrasound catheters is safe and feasible; it also provides anatomic and physiologic information. This feasibility study provides a foundation for wider clinical use of intracardic echocardiography.

Adolescent↗
PubMed1991

Intracardiac echocardiography: current developments.

Intracardiac echocardiography refers to the method of imaging cardiac structures from intracardiac locations with the use of ultrasound catheters. Advances in catheter-based interventional cardiologic procedures to treat cardiovascular lesions and the problems encountered during those procedures due to inadequate guidance provided by fluoroscopy have given the impetus to develop other guidance modalities. Experimental explorations with intracardiac ultrasound probes have indicated that detailed visualization of cardiac structures in real-time is possible by intracardiac ultrasound. Recent advances in catheter-based ultrasound technology make it feasible to safely pass small-sized catheters in humans into various intracardiac locations and acquire images of valvular structures and various chambers. Experience with 20 MHz ultrasound catheters indicates that high resolution images of normal and abnormal structures can be obtained if the catheter is manipulated close to the region of interest. The problem of the limited depth of field associated with 20 MHz catheters has led to the fabrication of catheters with lower frequency ultrasound elements. Experimental and clinical experience with 12.5 MHz ultrasound catheters points to the capability and potential of intracardiac echocardiography to not only display normal structures but also aid in the identification of valvular abnormalities, chamber dysfunction and pericardial effusions. In addition, aortic disorders such as acute dissection, coarctation and atherosclerotic disease could be delineated. Similarly, abnormalities involving the pulmonary arteries such as pulmonary embolism, organized thrombi, peripheral pulmonary arterial stenoses, and pulmonary hypertension-induced vascular changes could be recognized. Many modifications in the catheter design are being explored. With further work in the area of catheter technology and ultrasound image processing, intracardiac echocardiography is likely to become a clinical tool.

Animals↗
PubMed1991

Real-time, intracardiac, two-dimensional echocardiography: enhanced depth of field with a low-frequency (12.5 mhz) ultrasound catheter.

Advances in catheter-based ultrasound imaging technology allow for a unique opportunity to develop two-dimensional intracardiac echocardiography, an imaging method that could have significant clinical applications. In this study, we evaluated the potential of a new, percutaneous, 9-Fr prototype intracardiac echocardiographic catheter with a 12.5-MHz rotating crystal in 13 dogs. In all dogs, we were able to easily advance the intracardiac echocardiographic catheter into the right and left hearts percutaneously and obtain dynamic images of cardiac structures in various imaging planes. With the intracardiac echocardiographic catheter in the right atrium, the whole chamber could be visualized. Minor manipulation allowed visualization of the right atrium, right ventricle, and tricuspid valve in a two-chamber view; further maneuvering yielded four-chamber views. With advancement of the catheter into the right ventricle and pulmonary artery, the right ventricular cavity, right ventricular outflow tract, and pulmonary artery could be imaged. The intracardiac echocardiographic catheter in the aortic root allowed visualization of the pulmonary artery and its bifurcation, superior portions of the atria, interatrial septum, aortic valve, and the proximal left coronary artery. With the intracardiac echocardiographic catheter in the left ventricle, short-axis images of the whole left ventricle were obtained. Manipulating the catheter tip within the left ventricle, we could visualize the left ventricle, left atrium (LA), and the mitral valve in the long axis. We were also able to visualize and identify experimentally-induced ischemic regional left ventricular dyskinesis (four of of five dogs), aortic valvular tear (five out of five dogs), and pericardial effusion with right atrial collapse (two out of two dogs). Intracardiac echocardiography was not associated with any complications. We conclude that percutaneous, low-frequency intracardiac echocardiography with a 12.5-MHz, 9-Fr catheter yields cardiac images in many imaging planes with a good depth of field, allows identification of valvular, myocardial, and pericardial abnormalities, and has excellent clinical potential in the assessment of many cardiovascular disorders.

Animals↗
PubMed1991

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.

Blood Vessels↗
PubMed1991

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.

Animals↗
PubMed1991

Intracardiac echocardiography. Experimental observations on intracavitary imaging of cardiac structures with 20-MHz ultrasound catheters.

Recently catheter-based ultrasound devices have become available for obtaining high-resolution images of blood vessels. In this study we evaluated the feasibility of imaging cardiac structures using 20-MHz ultrasound catheters. In 25 dogs, the ultrasound catheter was advanced into the right and left heart chambers percutaneously. The intravascular devices yielded images of the right atrial wall, right and left ventricular myocardia, tricuspid, pulmonic, and aortic valves, and the great vessels. Although the small depth of field inherent to the frequency range of 20 MHz limited the visualization to only portions of the cardiac chambers, the images obtained were of high resolution and allowed easy identification of the various cardiac structures. Intracardiac echocardiography was easy to perform and did not result in damage to the cardiac structures. We conclude that intracardiac echocardiography using ultrasound catheters provides a new approach to cardiac imaging and that the development of lower frequency catheters could aid in extending the potential utility of intracardiac echocardiography.

Animals↗
PubMed1990

Electrophysiologic and electrocardiographic effects, efficacy and safety of encainide in malignant ventricular arrhythmias associated with coronary artery disease.

The electrophysiologic and electrocardiographic effects, efficacy and safety of encainide were evaluated in 48 patients with coronary artery disease undergoing programmed stimulation for ventricular tachyarrhythmias. The study group included 41 men and 7 women, aged 64 +/- 8 years (mean +/- standard deviation), who had presented with nonsustained ventricular tachycardia (VT) (4 patients), sustained VT (32), ventricular fibrillation (8) or unexplained syncope (4). The left ventricular ejection fraction averaged 34 +/- 13%. The arrhythmias induced at the baseline, drug-free electrophysiologic study included nonsustained VT in 8 patients, sustained VT in 35 and ventricular fibrillation in 5. All patients had failed greater than or equal to 1 class IA and a combination of class IA and IB agents (mean 2.2 +/- 1.1 drugs) before encainide. Oral encainide was given in a mean daily dose of 80 +/- 11 mg for greater than or equal to 3 days before repeat programmed stimulation. Encainide was discontinued before follow-up electrophysiologic testing in 5 patients due to spontaneous development of new sustained VT. Of the 43 patients undergoing electropharmacologic testing with encainide, 5 had no inducible arrhythmia. In 9 patients VT was inducible by fewer extrastimuli, in 2 patients a previously stable VT required cardioversion, whereas in 28 patients VT remained inducible by the same number of or more extrastimuli. Thus, encainide prevented the induction of VT or ventricular fibrillation in 5 of 48 patients (10%), while it had a possible proarrhythmic effect in 15 patients (31%). Of the 5 patients without inducible VT administered long-term encainide therapy, 1 returned within 4 weeks of hospital discharge with VT recurrence.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Intracardiac two-dimensional echocardiography in patients with pericardial effusion and cardiac tamponade.

The utility of intracardiac two-dimensional echocardiography in the identification of pericardial effusion was assessed in five patients with pericardial effusion and cardiac tamponade. A 20 MHz, mechanically rotating ultrasound catheter was used for intracardiac imaging. In all five patients, intracardiac echocardiography yielded high resolution of images of the right atrial cavity, the right atrial wall, and the pericardial effusion. In two patients, right atrial collapse could be identified during real-time imaging. Although the entire right atrial cavity and the pericardial effusion could not be displayed in a single imaging field because of the limited depth of field associated with the 20 MHz catheter, manipulation of the catheter allowed visualization of the pericardial effusion and the parietal pericardium in each patient. The effusion was seen to surround the superior vena cava, as well, in all patients. After pericardiocentesis, the reduction in the size of the effusion and increase in the right atrial cavity size could be recognized by intracardiac echocardiography. The introduction and manipulation of the ultrasound catheter was easily performed without any complications. This experience presents one clinical application for intracardiac echocardiography and indicates its potential value in the invasive cardiac laboratory.

Cardiac Catheterization↗