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Biomedical subjects

I Kronzon

Publications and source records attributed to I Kronzon.

At least 217 records · Page 12Linked to original sources
PubMed1982

Microbubble formation: in vitro and in vivo observation.

Injection of liquid through a catheter into the circulation is known to produce clouds of signals detected by sonography. Blood forced through a stenotic conduit produced sonographic clouding, and bubbles of 10-100 microns were observed were observed by light microscopy. The microbubbles persisted up to three and a half minutes. Microbubbles were observed in the microcirculation of the rat by placing the catheter tip into the descending aorta of 15 animals, viewing the mesentery at 400X magnification, and recording the results on videotape. Following injection of the rats' own blood, numerous microbubbles lodged promptly at the arteriolar level and obstructed blood flow for up to 200 sec before shrinking sufficiently to pass downstream and allow restitution of flow.

Animals↗
PubMed1982

Spasm of a normal or minimally narrowed coronary artery in the presence of severe fixed stenoses of the remaining vessels: clinical and angiographic observations.

Four patients with medically refractory unstable angina are presented. Each patient had ST-segment abnormalities during some episode of pain. Three patients had at least one episode of documented ST-segment elevation with their spontaneously occurring chest pain. One had recurrent ventricular tachycardia. Two patients had prior myocardial infarction. Angiography demonstrated localized left ventricular akinesis and a severe fixed stenosis in the coronary artery supplying the abnormal segment. There were severe, fixed lesions in two coronary arteries in two patients and in one vessel in two patients. After i.v. ergonovine maleate, coronary artery spasm was documented in a normal or minimally diseased coronary artery in each patient. In two patients, ergonovine-induced spasm not only occluded the vessel, but also markedly decreased retrograde filling of a vessel with severe, fixed narrowing. Each patient's characteristic symptoms appeared with the ergonovine-induced spasm. Thus, ergonovine maleate can provoke spasm of a normal coronary artery, even in the presence of severe fixed stenoses of the remaining vessels. This observation may have an important role in the diagnosis and clinical management of patients with chest pain.

Adult↗
PubMed1982

Reversible doxorubicin-induced congestive heart failure.

Doxorubicin hydrochloride is a chemotherapeutic agent highly effective against a wide range of neoplasms. A prime limiting factor to the administration of this drug is cardiotoxicity, which frequently develops when the cumulative dose exceeds 500 mg/sq m. Late cardiomyopathy, which may develop up to a year after therapy has been discontinued, was thought to be rapidly progressive and unresponsive to standard cardiac therapy. An adult who received 475 mg/sq m of doxorubicin hydrochloride experienced a cardiotoxic reaction one year after the completion of therapy. The patient responded to standard cardiac therapy. Resolution of left ventricular dysfunction was verified by echocardiography and radionuclide angiocardiography.

Doxorubicin↗
PubMed1981

Transvenous intracardiac echocardiography.

A specially designed ultrasonic transducer, 0.2 mm in length and 0.75 mm in diameter, operating at 7.5 megahertz and mounted on a thin flexible coaxial cable was advanced to the distal tip of a right heart or transseptal catheter in 20 patients during cardiac catheterization. Left atrial, aortic root and right atrial cavity size, pulmonary arterial diameter at various sites, right ventricular wall thickness and the width of a pericardial effusion were demonstrated. Tricuspid, pulmonary, and aortic valves were seen and their motion displayed. With the transducer positioned at the tip of a transseptal needle it could be recognized when it made contact with the interatrial septum. Puncture into the left atrium, avoiding such structures as the aorta, was facilitated in this fashion. No complications were encountered in any patient. Intracardiac echocardiography appears to be a safe, valuable adjunct to both conventional echocardiography and cardiac catheterization. Furthermore, recordings of structures that may be difficult or impossible to obtain with routine external echocardiography may be made possible.

Aortic Valve↗
PubMed1980

Single channel dual echocardiography.

An inexpensive method for obtaining simultaneous echograms from two or more cardiac areas is described. The measurement of systolic and diastolic time intervals, the identification of various auscultatory findings and the diagnosis of some valvular lesions are among the uses of such a technique.

Aortic Valve↗
PubMed1980

Propranolol: an unrecognized cause of central nervous system dysfunction in patients undergoing cardiopulmonary bypass.

An organic mental syndrome developed in a patient soon after he underwent repair of a dissecting thoracic aortic aneurysm. The operation was accomplished with cardiopulmonary bypass. Initially, the mental changes were thought to be related to the operation. However, they subsequently were shown to be associated with propranolol. The potential role of propranolol in inducing central nervous system disturbances is emphasized, and the literature on the subject is reviewed.

Aortic Dissection↗
PubMed1980

Echocardiographic patterns after mitral annuloplasty.

18 adolescents and children who underwent mitral annuloplasty for severe mitral regurgitation were evaluated by echocardiography. In 7 patients studied preoperatively, mitral valve excursion ranged from 25 to 56 mm with E-F slopes from 92 to 160 mm/sec. 5 of the 7 patients showed mitral valve prolapse. The left ventricle was dilated in 6 and the left atrium was dilated in 4 patients. Postoperatively, the mitral valve excursion decreased ( range 15-26 mm; p less than 0.01) as did the E-F slope (range 44-100 mm/sec; 0.10 greater than p greater than 0.05). The prolapse pattern disappeared and the left heart chambers decreased in size. In these 7 patients and in 11 others studied postoperatively only, a common echocardiographic pattern was that of early anterior motion of the posterior mitral valve leaflet, which was not present preoperatively and was, therefore, tentatively ascribed to the technique of annuloplasty repair. No calciferation and no definite mitral steosis has occurred in the follow-up of these patients to date. Persistent left atrial/left ventricular dilatation appeared related to residual mitral regurgitation with or without atrial fibrillation.

Adolescent↗
PubMed1980

Echocardiographic observations of paradoxic pulse without pericardial disease.

Echocardiograms were obtained in 10 normal patients and in 11 patients with respiratory insufficiency due to chronic obstructive lung disease (8) and to thoracic poliomyelitis (3). Only the eight patients with obstructive lung disease had paradoxic pulse. No patient had pericardial disease. The left ventricular internal dimension, stroke volume, and the mitral valve E-F slope and D-E excursion were measured. The inspiratory to expiratory ratio of each measurement was significantly lower in patients with obstructive lung disease than in normal subjects. The patients with thoracic poliomyelitis demonstrated almost no respiratory change in these measurements. The magnitude of the change in the measured factors probably relates to the degree of negativity of intrathoracic pressure during respiration. The inspiratory reduction of mitral valve motion and left ventricular internal dimension is not specific to tamponade but may be seen in patients who exhibit paradoxic pulse due to other conditions.

Cardiac Tamponade↗
PubMed1980

Two-dimensional echocardiography in mitral annulus calcification.

Mitral annular calcification, established by fluoroscopy, was studied by M-mode and two-dimensional echocardiography in 18 patients. M-mode echocardiography revealed the typical dense, linear echo of mitral annular calcification, but not its extent. Two-dimenstional echocardiography demonstrated a dense, elipsoidal echo at the junction of the left atrium and ventricle in the long axis view, and an area of calcification below the mitral valve in the short axis view. These patterns were not seen in 20 control patients without mitral annular calcification by fluoroscopy. Two-dimensional echocardiography establishes the site and extent of mitral annular calcification, minimizes the potential for diagnostic error associated with M-mode echocardiography, and is superior to M-mode echocardiography for the recognition of mitral annular calcification.

Aged↗