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Biomedical subjects

M Lev

Publications and source records attributed to M Lev.

At least 145 records · Page 8Linked to original sources
PubMed1980

Surgical anatomy of the atrioventricular valve in the intermediate type of common atrioventricular orifice.

The intermediate type of common atrioventricular (AV) orifice is represented by a spectrum of anomalies lying between persistent ostium primum with cleft aortic leaflet of the mitral valve and the complete form of common AV orifice. This is a study of 81 such hearts. These hearts do not have a distinct cleft in the aortic leaflet of the mitral valve, nor do they have a common valve, as seen in the complete form of common AV orifice. They may or may not have a ventricular septal defect. The surgical importance of the intermediate forms lies in the lack of sufficient valvular tissue on the left side to propertly fashion a mitral valve in many cases (41%).

Autopsy↗
PubMed1979

Endocardial cushion defect associated with cor triatriatum sinistrum or supravalve mitral ring.

Clinical and angiographic or autopsy data, or both, on three children with a subdivided left atrium (cor triatriatum) and an associated endocardial cushion defect are reviewed. (One child had ostium primum defect, and two had complete atrioventricular [A-V] canal.) A fourth patient demonstrates the difficulties in differentiating subdivided left atrium from supravalve mitral stenosis in the presence of an endocardial cushion defect. The clinical findings are greatly influenced by the endocardial cushion defect. A pressure gradient between the pulmonary wedge and (left or right) ventricular end-diastolic pressures in patients with an endocardial cushion defect indicates pulmonary venous obstruction and should alert one to the possibility of these combined lesions. The exact diagnosis is made with injections of angiographic contrast medium into the proximal and distal left atrial chambers, to documented the respective relations of the pulmonary veins, left atrial appendage and A-V valves to these atrial chambers. All three patients with an endocardial cushion defect and a subdivided left atrium had an associated patent ductus arteriosus. The common association of subdivided left atrium with intracardiac, pulmonary venous and aortic anomalies is again demonstrated.

Cardiac Catheterization↗
PubMed1979

Sphingolipid biosynthesis and vitamin K metabolism in Bacteroides melaninogenicus.

B. melaninogenicus provides a unique system for the study of the biosynthesis of an important group of lipids, the phosphosphingolipids. Sphingolipid biosynthesis can be repressed and induced by depletion and restoration of vitamin K. At least one enzyme involved in sphingolipid biosynthesis from the microorganism can be solubilized and so purified by conventional methods. Pathways involved in biosynthesis may differ from hitherto postulated pathways, for example, the incorporation of NH4+ into ethanolamine residue of ceramide phosphorylethanolamine. Moreover, the derivation of mutants defective in steps in sphingolipid biosynthesis would be of great value in these studies.

Animals↗
PubMed1979

Truncus arteriosus communis with intact ventricular septum.

This is the first documented case of truncus arteriosus communis with intact ventricular septum in which extensive clinical, haemodynamic, angiographic, and pathological data are available. Angiography suggested the presence of two discrete semilunar valves but necropsy showed a basically single semilunar valve. This case fills a gap in the spectrum of aorticopulmonary, truncal, and infundibular septal defects, and reinforces the belief that the essence of truncus arteriosus communis is a single semilunar valve, common to both ventricles, which need not be associated with the defects in the adjacent parts of the structural continuum.

Angiocardiography↗
PubMed1979

Congenital abnormalities of the conduction system in two patients with tachyarrhythmias.

Serial sections of the conduction system (CS) were performed in two patients with recurrent tachyarrhythmias. Case 1, a 34-year-old female who had dual atrioventricular (AV) nodal pathways with recurrent paroxysmal supraventricular tachycardia, committed suicide. Autopsy revealed an abnormally formed atrial septum with insertion of eustachian valve on the AV part of the pars membranacea. The intercuspid portion of the pars membranacea was muscular. The AV node was located adjacent to the membranous part of the ventricular septum rather than the central fibrous body. In addition, there was an accessory anterior AV node on the parietal wall of the right atrium. Case 2, a 13-year-old boy with history of recurrent ventricular tachycardia, died suddenly. CS revealed a right-sided, markedly septated bundle. The first part of right bundle branch was divided into three parts, which later joined together. Both cases showed fatty infiltration of the atrial septum, more than normal for the age of the patients. The relationship of the recurrent tachyarrhythmias to the congenital abnormalities in the CS in the two cases and the fatty infiltration is reviewed.

Adolescent↗
PubMed1979

The conduction system in hypoplasia of the aortic tract complex.

This is a study of the course of the conduction system in two cases of hypoplasia of the aortic tract complex, one with mitral stenosis and the other with mitral atresia. In both there was a posterior atrioventricular (AV) node which formed the AV bundle. In case 1 the bundle was short and bifurcated early. The branching bundle gave off a large left bundle branch (LBB), many Mahaim fibers to the septum and a small right bundle branch (RBB). In case 2 the AV node was divided into two parts which formed two posterior bundles which joined together to form a short branching bundle. Instead of a LBB there were profuse Mahaim fibers passing from the branching bundle to the depths of the ventricular septum. The RBB was large. The abnormalities seen in the conduction system particularly in the LBB are discussed from the embryologic stand-point.

Aorta↗
PubMed1979

Straddling and displaced atrioventricular orifices and valves.

This is an anatomic study of 96 hearts with straddling or displaced atrioventricular (AV) valves and orifices. In the complete form, both the annulus and the peripheral connections of either AV valve straddle a ventricular septal defect (VSD) and connect to both ventricles. In the annular form, only the annulus, and in the peripheral type only the peripheral connections of the valve are found in both ventricles. In displaced AV valve, the entire annulus and periphery of one AV valve are displaced into the opposite chamber. These anomalies are commonly seen in complete transposition with or without ventricular inversion, and in double outlet right or left ventricle. Straddling mitral valve is frequently seen in the Taussig-Bing heart. Any type of VSD may be associated with straddling tricuspid valve; however, they usually are of the AV canal type. Straddling and displaced AV valves should be differentiated from criss-cross hearts in which both AV valves are completely connected to oppositely placed ventricles.

Atrioventricular Node↗
PubMed1979

Failure of surgery in preexcitation. Correlation with pathologic findings.

A 37-year-old man with mitral stenosis and recurrent drug-resistant paroxysmal atrial fibrillation, paroxysmal supraventricular tachycardia, and preexcitation, underwent two surgical attempts to ablate an anomalous pathway (AP). Electrophysiologic study demonstrated a left posterior AP with a short antegrade refractory period. Epicardial mapping at the time of mitral valve replacement (left lateral thoracotomy) suggested a posterior right AP. Mitral valve replacement and incision of the left atrial wall failed to cure preexcitation. Epicardial mapping at a second operation (median sternotomy) demonstrated a subepicardial left posterior AP. Right atrial and atrial septal incisions failed to cure preexcitation. Serial section of the atrioventricular rings and conduction system demonstrated an intact left posterior anomalous atrioventricular muscle bundle with surgical incision placed above the plane of the mitral anulus.

Adult↗
PubMed1979

Taussig-Bing anomaly with straddling mitral valve.

Five patients with the left-sided or intermediate type (Lev) of the Taussig-Bing anomaly were found to have an associated straddling of the mitral valve. In four patients the anomaly of the mitral valve was not recognized preoperatively, and all four died postoperatively. The persistent subpulmonic obstruction caused by the abnormal attachment of the anterior mitral leaflet is considered a significant factor in the poor operative outcome. Retrospective study of angiograms in these four patients revealed diagnostic clues of straddling mitral valve which enabled us to diagnose a fifth patient angiographically and confirm the diagnosis by cross-sectional echocardiography. A surgical approach to correct this association of abnormalities is proposed which avoids operating upon the mitral valve. Its function is thereby preserved, yet the hemodynamic problem caused by the straddling is bypassed. The fifth patient in this series was successfully treated by the proposed operative method.

Adolescent↗
PubMed1979

The relationship between single ventricle and small outlet chamber and straddling and displaced tricuspid orifice and valve.

This paper deals with the anatomic differences between single ventricle and small outlet chamber, straddling tricuspid orifice and valve, and displaced tricuspid orifice and valve. In single ventricle, both atrioventricular orifices enter a chamber which contains the sinuses of both definitive ventricles, while a small outlet chamber represents the definitive infundibulum of the right ventricle. In straddling tricuspid orifice and valve, the primitive left ventricle contains the sinus of the definitive infundibulum of the right ventricle. In straddling tricuspid orifice and valve, the primitive left ventricle contains the sinus of the definitive left ventricle and also a portion of the sinus of the definitive right ventricle. The primitive right ventricle contains the infundibulum and part of the sinus of the definitive right ventricle. In displaced tricuspid orifice, the primitive left ventricle contains the sinus of the definitive left and almost all of the sinus of the definitive right ventricle. However, a posterior ventricular septum is formed, so that a portion of sinus or apical recess of the definitive right ventricle is included in the primitive right ventricle together with its infundibulum. Possible embryologic speculations are offered to account for these entities. The differences in the anatomy of these entities may be important to the surgeon.

Heart Defects, Congenital↗
PubMed1979

Conduction system in two cases of sudden death two years after the Mustard procedure.

This report describes a serial section examination of the conduction system in two children who died suddenly 2 years following the Mustard procedure for complete transposition. The first child manifested sinus rhythm alternating with junctional rhythm in the last year of life. The second child, 2 months before death, had first-degree atrioventricular (AV) block which progressed to second-degree block with 2:1 conduction alternating with a junctional rhythm with AV dissociation. Examination of the conduction system in both cases revealed the approaches to the sinoatrial (SA) and the AV nodes to be markedly fibrosed. In addition, in Case 1 the SA node was interrupted by sutures and in Case 2 the SA node was considerably fibrosed. The arrhythmias produced and the probable cause of sudden death in both cases may be related to surgical injury to the approaches to the SA and AV nodes. This study and the review of the literature emphasize the necessity of maintaining the integrity of the SA node, the approaches to the SA and AV nodes, and the superior preferential pathway while performing the Mustard procedure for complete transposition.

Atrioventricular Node↗
PubMed1978

Echocardiographic features of total anomalous pulmonary venous drainage into the coronary sinus.

Echocardiograms were obtained from five infants with total anomalous pulmonary venous drainage to the coronary sinus or the portal system or the superior vena cava and from one child with a secundum atrial septal defect and a large coronary sinus due to persistence of the left superior vena cava. The results demonstrate that an enlarged coronary sinus is positioned consistently posterior to the left atrium in approximately the same horizontal plane as the aortic valve. Echocardiographically the coronary sinus can be located as an echo complex behind the left atrium by using the aortic root as a reference point. The echo complex can be differentiated from the other spurious echoes in the left atrium by its characteristic phasic motions. The additional demonstration of the enlarged common pulmonary venous chamber behind the right atrium confirms the diagnosis of anomalous pulmonary venous drainage to the coronary sinus. For other types of anomalous pulmonary venous return, anatomic diagnosis with single crystal M mode echocardiography is not always possible because of the positional variability of the common pulmonary venous chamber in relation to the left atrium.

Coronary Vessel Anomalies↗
PubMed1978

Lack of connection between the atria and the peripheral conduction system in a case of corrected transposition with congenital atrioventricular block.

This is the first documented histologic study of the heart of a patient with corrected transposition of the great vessels and congenital atrioventricular (A-V) block with no connection between the atria and an anterior type of peripheral conduction system. Musculature in the superior (anterior) walls of both atria was absent, as was the anterior A-V node. The peripheral conduction system began with the bundle of His. In place of the absent atrial musculature, fibrosis and calcification were present. The relation of laboratory evidence of connective tissue dyscrasia in the mother to the congenital A-V block in the child is discussed.

Adult↗
PubMed1978

The course of the conduction system in dextrocardia.

This is a serial section examination of the conduction system of five hearts of various types of dextrocardia. In one case of dextroversion the conduction system was found to be normal. In one case of mirror-image dextrocardia the conduction system was normal but in the opposite spatial position. In one heart of mixed (discordant) dextrocardia, the sinoatrial node was in correct morphologic position. There were two atrioventricular nodes - a posterior node close to the coronary sinus and an anterior node in the roof of the morphologic right atrium. They formed two separate bundles which joined in the left ventricle to form a "sling". In two cases of presumptive mirror-image dextrocardia, with a common atrium in situs inversus according to the morphology of the atrial appendages, with common atrioventricular orifice (CAVO), the sinoatrial node was situated in wrong positions. Two atrioventricular nodes and bundles again formed a sling. There are various types of slings in discordant dextrocardia.

Atrioventricular Node↗