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Biomedical subjects

A R Levin

Publications and source records attributed to A R Levin.

At least 37 records · Page 2Linked to original sources

Cardiac catheterization indications, techniques, interpretation, and complications.

In pediatric patients with congenital or acquired heart disease, cardiac catheterization and visual contrast studies provide a complete hemodynamic, functional, and anatomical picture of the patient's abnormality. The information obtained must be interpreted in light of the patient's history and clinical findings, together with other information obtained by noninvasive techniques. The procedure should be undertaken only after careful planning, yet the approach should be flexible, so that an alternate direction may be pursued should the unexpected be found. Each piece of information should be collated in step-wise fashion until the entire situation is clarified. Such procedures provide a wealth of information on which the cardiologist can base recommendations for continued medical management or surgical intervention.

Angiocardiography↗

Atrial myxoma mimicking a collagen disorder.

A 14-year-old boy had a protracted illness characterized by bilateral tenderness and weakness of the extremities; the illness was considered to be a connective tissue disease similar to polymyositis. Not until nine months later, when the patient had new cardiac murmurs, pulmonary edema, and then a cerebrovascular accident, was the true nature of his illness suspected. The diagnosis of left atrial myxoma with the triad of constitutional, obstructive, and embolic effects was confirmed by echocardiographic studies and cardiac catheterization. The tumor was successfully removed.

Adolescent↗

Aortico-left ventricular tunnel with natal cardiac failure.

Presented is a case of aortico-left ventricular tunnel in a 1-day-old girl who was in shock and severe cardiac failure. The clinical, auscultatory, hemodynamic and angiocardiographic, surgical, and pathologic findings in this case and from the 21 others reported in the literature are described. The diagnosis should be considered in an infant or child with signs of aortic insufficiency. Aortography is diagnostic when a localized supravascular aortic channel communicating with the left ventricle is opacified. Definitive treatment is surgical, though residual aortic insufficiency is common.

Angiocardiography↗

Intracardiac conduction intervals in children with congenital heart disease: comparison of His bundle studies in 41 normal children and 307 patients with congenital cardiac defects.

His bundle electrograms were recorded in 348 patients aged 2 months to 24 years following routine diagnostic cardiac catheterization. Among 41 children found to be free of anatomic or hemodynamic abnormality the following mean values were obtained: P-H interval, 93.4 +/- 15.3 msec; P-A time, 21.2 +/- 7.1 msec; A-H interval, 72.2 +/- 15.9 msec; and H-V interval, 39.8 +/- 5.2 msec. The remaining 307 patients were analyzed by diagnosis of congenital heart disease. The mean P-H interval was found to be significantly increased in both ostium primum and secundum atrial septal defect (ASD) with A-H prolongation in primum ASD and P-A prolongation in secundum ASD. The mean H-V interval was significantly prolonged in ostium primum ASD and in patients with severe aortic stenosis, aortic insufficiency. and mitral regurgitation. Grouping of the patients physiologically revealed that patients with moderate-to-severe right ventricular volume overload had P-H prolongation, and patients with severe left ventricular volume or pressure overload had H-V prolongation. The clinical implications of these findings are discussed.

Adolescent↗

Membranous subaortic stenosis and patent ductus arteriosus.

Six children (five of them girls) each initially had a large patent ductus arteriosus with auscultatory, radiologic, and electrocardiographic findings typical of that lesion. After surgery for the lesion, an ejection-type basal systolic murmur led to detection of discrete membranous subaortic stenosis, which became worse in late childhood. The murmur became louder, the systolic pressure gradient increased from slight to significant, and hypertrophic subaortic stenosis or aortic insufficiency (or both) developed in the older children. Surgical excision of the membrane afforded improvement, except in one patient with the most severe involvement. Because of the unexpected finding of discrete membranous subaortic stenosis in these infants and young children who had undergone surgery for a large patent ductus arteriosus and because of the treacherous worsening of the effects of the discrete membranous subaortic stenosis as childhood progressed, it is important that those patients with a persistent systolic murmur after ductal ligation not be discharged from cardiac follow-up as cured. Serial cardiac catheterization during the growing years appears to be the most accurate way of detecting worsening discrete membranous subaortic stenosis, so that the membrane can be excised before severe complications occur.

Angiocardiography↗

Contrast media with and without calcium for cardioangiography in children.

The possible beneficial effects of added calcium ions to contrast media to diminish myocardial toxicity was evaluated in 93 cardiac catheterizations with cardioangiography, performed in 50 children and adolescents. Two contrast media with equal iodine content (370 mg/ml) and similar physical properties were used: Isopawue-370, containing 0.34 mg calcium/ml, and Renografin-76, not containing calcium. It is concluded that addition of calcium to contrast media for cardioangiography in children and adolescents does not alter their myocardial, fluid or electrolyte effects when injected selectively into the cardiac chambers or great vessels.

Adolescent↗

Appearance of the interventricular septum in obstructive lesions of the left ventricular outflow tract.

Measurements of the thickness of the septum were made in 26 cardiac specimens and in 13 patients. There were 10 normal specimens, five with aortic stenosis, two with asymmetric septal hypertrophy, four with hypertensive cardiovascular disease, and five with idiopathic cardiomyopathy. Patient measurements were obtained by visualizing the septum during simultaneous left and right ventriculography on angiograms obtained in the left anterior oblique projection. Four patients were normal, five had aortic stenosis, and four had a symmetric septal hypertrophy. Measurements derived from normal cardiac specimens and angiographic appearance suggested that the normal septum is a smooth-walled structure with right and left ventricular surfaces parallel, diverging only slightly at the apex of the ventricle. In aortic stenosis and idiopathic cardiomyopathy, the septum tends to be biconvex with maximal thickening in its middle third. Hypertensive cardiovascular disease produces uniform septal thickening, resembling an exaggeration of normal. However, in asymmetric septal hypertrophy no consistent patterns of hypertrophy or septal thickening are evident; bulging can be present at any point along the left ventricular surface of the septum.

Aortic Valve Stenosis↗

Assessment of left ventricular function in secundum atrial septal defect: evaluation by determination of volume, pressure, and external systolic time indices.

Left ventricular function and volume data from 17 control subjects and 27 young patients with secundum atrial septal defect (ASD) without overt left or right ventricular failure were compared. ASD patients were subdivided in low shunt (Qp/Qs less than 2.0) and high shunt (Qp/Qs larger than or equal to 2.0) groups. Mean left ventricular (LV) stroke volume was significantly less in ASD patients (46 +/- 16 ml/m2 in the low shunt and 44 +/- 9 ml/m2 in high shunt group) compared with control patients (51 +/- 13 ml/m2, P less than 0.01 and P less than 0.02, respectively). There was no significant difference in mean left ventricular end-diastolic volume (LVEDV) between any group of patients (control subjects 67 +/- 17 ml/m2; low shunt ASD 66 +/- 17 Ml/m2, and high shunt ASD 62 +/- 12 ml/m2). High shunt ASD had a significantly lower cardiac index compared with control patients (5.0 liters/min/m2 vs. 5.9 liters/min/m2, P less than 0.02). Both low shunt and high shunt ASD showed significantly lower stroke work indices than control subjects (42 +/- 13 GmM/m2 and 37 +/- 8 GmM/m2 compared with 51 +/- 14 GmM/M2 , P less than 0.05 and P less than 0.001, respectively) but only the high shunt group had a significantly lower peak systolic pressure (94 +/- 12 mm Hg vs. 109 +/- 11 mm Hg for control patients, P less than 0.01). There was no significant difference between the control and ASD groups in LV end-diastolic, mean right atrial, right ventricular end-diastolic, and pulmonary pressures. External systolic time intervals were compared in 5 control and 12 ASD patients. There was no significant difference between the two groups of patients in absolute values or indices for pre-ejection period, ejection time, or electromechanical systole. However, the ratio of the pre-ejection period index to left ventricular ejection time index (PEPI/LVETI) was significantly higher in ASD patients (P less than 0.05). In young subjects with large shunt ASD, certain indicators of left ventricular function are depressed. Evaluation of PEPI/LVETI may allow noninvasive determination of LV function.

Adolescent↗

Silent anomalies of the urinary tract and congenital heart disease.

Postangiocardiographic screening of infants and children with congenital heart disease for silent anomalies of the urinary tract yielded an incidence of 7.7 percent in 260 so studied. The incidence was 29 percent in 21 babies who came to autopsy and had been studied at catheterization but without this screening. Patients with atrial septal defect had the highest incidence of urinary tract anomalies, while those with ventricular septal defect and tetralogy had an average incidence. Some of the lesions discovered were potentially significant even though silent. They were found with sufficient frequency to warrant routine use of this screening technique at cardiac catheterization.

Abnormalities, Multiple↗

The response of the right ventricle to experimentally induced pulmonary artery obstruction.

Banding of the main pulmonary artery was undertaken in 11 litter-mate puppies and 8 young adult beagle dogs to study the response of the right ventricle to pressure loading. Five puppies and 3 young adult dogs acted as controls, undergoing sham surgical procedures without pulmonary artery banding. In one banded puppy and one banded young adult dog, adequate banding was not achieved and each was subsequently considered with its respective control group. A trans-band gradient of 15 mm Hg or greater was deemed a successful banding procedure. Banded puppies showed an increase in the trans-band pressure gradient in the year following surgery whereas young adult dogs showed a fall in the gradient, despite satisfactory banding as shown by cardiac catheterization 14 days after surgery. Cardiac muscle analyses indicated that the right ventricle of puppies responded to pulmonary banding by an increase in total organ weight, total tissue protein, DNA and RNA without altering the protein/DNA and RNA/DNA ratios. By contrast, young adult dogs showed only slight and insignificant increases in the protein/DNA and RNA/DNA ratios. Thus the response of the right ventricle to pulmonary artery banding in puppies is hyperplastic in nature, while in young adult animals the response to a similar stress load is with mild muscular hypertrophy and dilatation. This differential cellular response to the same stimulus based on the age of the organism is another demonstration of the principle that growth responses in the young involve cellular proliferation while those in the adult consist primarily of cell enlargement. It is, therefore, perhaps erroneous to refer to cardiac enlargement in newborns and infants as cardiac hypertrophy.

Animals↗