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Biomedical subjects

M Lev

Publications and source records attributed to M Lev.

At least 163 records · Page 9Linked to original sources
PubMed1978

Inexcitable right ventricle and bilateral bundle branch block in Uhl's disease.

A 29-year-old female with Uhl's anomaly developed complete atrioventricular (A-V) block. His bundle studies revealed block distal to the His bundle recording site with narrow QRS complexes. Right ventricular capture could not be obtained and despite successful left ventricular epicardial pacing, the patient died. Autopsy revealed absence of myocardium in most areas of the right ventricle and the right side of the ventricular septum with a normal tricuspid valve. Conduction system examination revelaed total destruction of both bundle branches. This is the first case where bilateral bundle branch block is shown to be present in Uhl's anomaly. Narrow QRS complexes probably reflected the absence of right ventricular forces.

Adult↗
PubMed1978

Absent tricuspid valve with aortic atresia in mixed levocardia (atria situs solitus, L-loop). A hitherto undescribed entity.

Clinical, angiographic and pathologic features are described in a 36-hour-old male infant with mixed (discordant) levocardia, aortic valve atresia, absent tricuspid (left atrioventricular) valve and resultant massive cardiomegaly. This is the first reported case of this type of complex in a heart with discordant chambers. A possible embryologic explanation is offered for the concomitant presence of semilunar valve atresia and absence of the tricuspid valve.

Aortic Valve↗
PubMed1977

The atrial septal defect-patent ductus arteriosus complex.

Both atrial septal defect and patent ductus arteriosus are common isolated lesions, each accounting for approximately 10% of the total incidence of congenital heart diseases. Yet, the combination of these defects, without other significant cardiac lesions, is infrequent. We review the clinical and pathologic data on 16 patients with this combination of defects, including cardiac catheterization data on eight patients. In patients with this combination, we found an unusually high incidence of severe pulmonary hypertension, multiple noncardiac anomalies, mental retardation, and early mortality.

Abnormalities, Multiple↗
PubMed1977

Congenital pulmonary atresia with tricuspid insufficiency: morphologic study.

In an anatomic study of 21 cases of pulmonary atresia with tricuspid insufficiency (pulmonary atresia with intact ventricular septum, type II), the morphologic features of the tricuspid valve and the right ventricle were found to differ greatly from those seen in pulmonary atresia with tricuspid stenosis (pulmonary atresia with intact ventricular septum, type I). Morphologically, pulmonary atresia with tricuspid insufficiency (type II) has a greater resemblance to Ebstein's disease with pulmonary atresia than to type I pulmonary atresia. The anomaly may be more amenable to surgery than pulmonary atresia with tricuspid stenosis because the right ventricle in the former may be converted into a functional chamber by a valvotomy combined with a shunting procedure and atrial septostomy.

Female↗
PubMed1977

Conduction system in a patient with Prinzmetal's angina and transient atrioventricular block.

His bundle recordings obtained during and between attacks of Prinzmetal's variant angina and transient atrioventricular (A-V) block were followed by a comprehensive serial section study of the conduction system in a 33 year old woman. Recordings between attacks showed normal A-H and H-V intervals. During an attack there was block proximal to the His bundle recording site. Pathologic studies revealed severe narrowing of the right coronary artery. Arteriolosclerosis of the heart was diffuse. Insignificant changes were found in the approaches to the A-V node and the A-V node itself. Major changes found in the left bundle branch had no counterpart in the electrocardiogram; the discordance in these findings is discussed.

Adolescent↗
PubMed1977

Energy-dependent incorporation of sphingolipid precursors and fatty acids in Bacteriodes melaninogenicus.

Washed cells of Bacteroides melaninogenicus are unable to incorporate the sphingolipid precursor 3-ketodihydrosphingosine (3KDS) or dihydrosphingosine into the complete sphingolipids ceramide phosphorylethanolamine (CPE) and ceramide phosphorylglycerol (CPG), whereas growing cultures are able to do so. This result suggested that an energy source was required by washed cells to initiate the incorporation of 3KDS. Investigation of a number of energy sources for B. melaninogenicus showed that glutamine was active in driving the incorporation of 3KDS. This system shows saturation kinetics. Besides glutamine, only asparagine and reduced nicotinamide adenine dinucleotide (NADH) are effective; glutamate and other compounds are inactive. The glutamine-driven system is sensitive to 2,4-dinitrophenol, azide, N,N'- dicyclohexylcarbodiimide, and carbonyl cyanide m-chlorophenylhydrazone. Asparagine plus NADH shows a synergistic effect in stimulating the incorporation of 3KDS into CPE and CPG in washed cells. However, glutamine plus NADH and glutamine plus asparagine show no such synergy. The cytochrome-free mutant of B. melaninogenicus, strain S, incorporates 3KDS in a manner similar to the parent strain when glutamine is used to drive the reaction; NADH or asparagine, however, are ineffective when used with strain S. Vitamin K-depleted cells of B. melaninogenicus are similar to vitamin K-grown cells, when glutamine or NADH is used to drive the 3KDS incorporation. Glutamine and NADH are also effective in stimulating the incorporation of palmitate and acetate by washed cells of B, melaninogenicus. Increased incorporation of these fatty acids into CPE, CPG, 3KDS, and other phospholipids is significantly increased by the presence of glutamine or NADH. Thus, energization of the membrane of B. melaninogenicus by glutamine or the electron transport system by NADH or asparagine is required for sphingolipid and other phospholipid synthesis. The relationship of this energization to possible transport of sphingolipid precursors is discussed.

Acetates↗
PubMed1977

Electrophysiological and anatomical observations on the heart of the African lungfish.

Electrophysiological and histological observations were made on the heart of the African lungfish. Impulse origin and propagation were studied using simultaneously recorded epicardial and pericardial electrograms. The primary pacemaker site in the lungfish was found to be at the sinus venosus at its junction with the left cardinal vein. Under a variety of circumstances, pacemaker function shifted to other sites. In response to stress, probably under vagal influence, the regular and rapid sinus venosus rate was generally superseded by an irregular and slower atrial pacemaker. Heart rate and sinoatrial and atrioventricular conduction times varied with changes in temperature [Q10=3.77, 2.55, and 5.46, respectively]. Although alterations in impulse formation and conduction did occur, the site of impulse formation and the patterns of conduction between heart chambers were usually fixed, implying the existence of an organized conduction system. Nonetheless, extensive histological study failed to disclose either organized nodal structures or specialized conduction pathways.

Africa, Central↗
PubMed1977

The conduction system in tricuspid atresia with and without regular (d-) transposition.

This is a serial section examination of conduction system in six hearts with tricuspid atresia. Four had regular (d-) complete transposition and two did not have transposition. The conduction system was more or less the same in all the hearts. The atrioventricular (A-V) node was in the normal position posteriorly and was short. The A-V bundle was situated in the left ventricular aspect of the subendocardium and passed posteriorly to the ventricular septal defect. Even though this type of conduction system is abnormal in some respects, it is not the type one finds in single ventricle with small outlet chamber with regular (d-) transposition. In those hearts an anteriorly located A-V node is present. These findings further substantiate the concept that tricuspid atresia with or without transposition is not a form of single (primitive) ventricle.

Atrioventricular Node↗
PubMed1976

Mid-ventricular obstruction: a variant of obstructive cardiomyopathy.

In two patients with clinical and catheterization findings of hypertrophic obstructive cardiomyopathy, the level of intraventricular obstruction was found to be in the mid-ventricular area rather than at the junction of the inflow and outflow tracts. One patient died suddenly shortly after unsuccessful outflow tract myectomy. In vivo recognition of this probably rare variant form of obstructive cardiomyopathy rests mainly on the angiograhic appearance of the left ventricle and on the recording of pressures in multiple sites of the left ventricular cavity. Surgical relief of the obstruction in these patients is not likely to be obtained by a transaortic left ventricular outflow myectomy but may require either papillary muscle resection by the transatrial or transventricular approach or mid-ventricular septectomy, or both.

Adult↗
PubMed1976

Mitral valve malformation of Ebstein type in absence of corrected transposition.

The first documented case is reported of mitral valve malformation of the Ebstein type in the absence of corrected transposition. In this case, the ring of the inferior leaflet of the mitral valve was displaced downward into the left ventricle, dividing the latter into a proximal atrialized and a distal effective ventricular chamber. The anterior leaflet was not displaced. The chordae tendineae of both leaflets were thickened. The papillary muscles were hypertrophied and abnormal in architecture. The outflow tract of the effective left ventricle was shortened. The valve leaflets were thickened, and the mitral valve was probably insufficient.

Chordae Tendineae↗
PubMed1976

Pathologic correlations in a case of complete heart block with split His potentials resulting from a stab wound of the heart.

A 23 year old previously healthy man was stabbed in the anterior chest. This resulted in a ventricular septal defect and complete atrioventricular (A-V) block. The electrocardiogram revealed complete A-V block with a QRS pattern of right bundle branch block. His bundle recordings 26 days later revealed A-V dissociation with split His potentials (P-H1 interval of 100 msec and H2-V interval of 40 msec). During the study the escape QRS shifted from right to left bundle branch block with H2 potentials still preceding each QRS interval with H2-V intervals of 40 msec. A permanent pacemaker was implanted because of persistent congestive heart failure and bradycardia due to A-V block. The patient subsequently became asymptomatic. He died suddenly 3 1/2 years later. Pathologically there were sizable openings in both the tricuspid and mitral valve substance and a ventricular septal defect involving the pars membranacea and part of the adjacent muscular septum. Serial sections of the conduction system revealed total destruction and fibrous replacement of the bifurcation and beginning of the right and left bundle branches and subtotal fibrous replacement of the branching bundle. Thus, the bifurcation of the bundle of His was totally absent at autopsy despite apparent electrophysiologic evidence of its existence 26 days after the stab wound. A possible explanation for this discrepancy is the subsequent fibrosis of the bifurcation produced by hemodynamic changes at the lower margin of the ventricular septal defect.

Action Potentials↗
PubMed1976

Subdivided left atrium: an expanded concept of cor triatriatum sinistrum.

Twenty-four hearts with cor triatriatum were studied. On the basis of this material and a review of the literature a new classification of "subdivided left atrium" is proposed. Tye A, the most common form of subdivided left atrium, is the classic cor triatriatum with its multiple variations of partial anomalous pulmonary venous drainage; the fossa ovalis can be related to the proximal left atrial chamber (type A, a) or the distal left atrial chamber (type A, b). Type B hearts are related to (but not identical with) total anomalous pulmonary venous drainage into the coronary sinus; the coronary sinus opening is atretic in these hearts; abnormal defects connect the proximal left atrial chamber usually with the right atrium only, rarely also with the distal left atrial chamber. The Type C heart, first reported in this paper, has a superiorly and medially situated proximal chamber, located between the right and distal left atrium; it does not receive any pulmonary veins; the coronary sinus is normally formed. Current morphogenetic hypotheses that satisfactorily explain the Type A b and B heart fail to account for the Type A a and C heart.

Adult↗
PubMed1976

Pathologic correlations in three cases of bilateral bundle branch disease with unusual electrophysiologic manifestations in two cases.

Examination of the conduction system in three patients with bifascicular block who had electrophysiologic studies forms the basis for this report. Patients 1 and 2 had left bundle branch block and Patient 3 right bundle branch block and left axis deviation. The H-V interval was prolonged in each case (70, 65 and 60 msec, respectively). Serial section examination of the conduction system revealed sclerodegenerative involvement of both bundle branches in all cases. In Case 1, atrial extrastimulus testing converted left to right bundle branch block; in Case 2, it delineated a sinus echo zone with repetitive sinus nodal reentrance. In the latter case serial section revealed extensive amyloid infiltration of the approaches to the sinoatrial (S-A) node and the atrial preferential pathways. In Case 3, with right bundle branch block and left axis deviation, serial section revealed greater involvement of the anterior part of the main left bundle branch than of the posterior portion as well as involvement of the second part of the right bundle branch. The study revealed excellent correlation between electrophysiologic and pathologic findings in three cases of intraventricular conduction disease and demonstrated an anatomic basis for the electrophysiologic findings resembling alternating bilateral bundle branch block. Sinus nodal reentrance may be related to disease in the approaches to the S-A node thereby causing delay in perinodal tissue allowing sinus reentrance. Finally in Case 3, the anatomic substrate for left axis deviation may lie in a greater involvement of the anterior portion than of the posterior portion of the main left bundle rather than in the corresponding portions of the periphery.

Aged↗