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Biomedical subjects

R H Anderson

Publications and source records attributed to R H Anderson.

At least 343 records · Page 19Linked to original sources
PubMed1988

Measurements of the dimensions of the aortic and pulmonary pathways in the human fetus: a correlative echocardiographic and morphometric study.

Thirty normal hearts from fetuses aborted at 10-33 weeks' gestation were measured directly and the results were compared with echocardiographic measurements in 20 normal live fetuses of 23-27 weeks' gestation. The diameters of the aorta, aortic isthmus, pulmonary arteries, and arterial duct were measured at standard levels and expressed as a ratio of the diameter of the ascending aorta. The ratios for the isthmus, the duct, and the right pulmonary artery were: 0.63 (0.11), 0.51 (0.13), 0.56 (0.10) respectively for the direct measurement and 0.73 (0.07), 0.7 (0.08), 0.62 (0.06) respectively at echocardiography. These results show that in mid-gestation the isthmus of the human fetus is not as small as that reported in animal models. This indicates that the distribution of the fetal circulation may not be the same either.

Aorta↗
PubMed1988

The determination of atrial arrangement by examination of appendage morphology in 1842 heart specimens.

The morphology of the atrial appendages was examined in 1842 specimen hearts from patients with congenital lesions. The external and internal features that permitted the identification of the right and left appendages were studied in detail in one tenth of the hearts. These results were compared with a similar analysis of 25 normal hearts. This study showed that criteria for identification of right and left appendages were reliable. Application of these criteria to the overall collection identified the usual arrangement in 1776 (97%) hearts, a mirror image arrangement in eight (0.4%); left atrial isomerism in 22 (1.2%); and right atrial isomerism in 36 (1.9%). Fourteen (0.81%) had juxtaposed atrial appendages (13 with usual arrangement and one with left isomerism). This did not interfere with identification of the left and right atria on the basis of appendage morphology. In only two cases did the determination by atrial morphology produce a result that was inconsistent with the arrangement of the other thoracoabdominal organs. Further examination of the atria in these showed a mistake had been made in the initial assessment. The atrial arrangement can be accurately determined by the morphology of the atrial appendages.

Child↗
PubMed1988

Localisation of atrial natriuretic peptide immunoreactivity in the ventricular myocardium and conduction system of the human fetal and adult heart.

Atrial natriuretic peptide immunoreactivity was found in ventricular and atrial tissues with specific antisera raised to the amino and carboxy terminal regions of the precursor molecule. In 13 developing human hearts (7-24 weeks' gestation) the immunoreactivity was concentrated in the atrial myocardium and ventricular conduction system but it was also detected in the early fetal ventricular myocardium. Immunoreactivity in five normal adults was largely confined to the atrial myocardium although it was also found in the ventricular conduction tissues of hearts removed from 10 patients who were undergoing cardiac transplantation. The ventricular conduction system is an extra-atrial site for the synthesis of atrial natriuretic peptide. In the failing heart this synthesis may be further supplemented by expression of the gene in the ventricular myocardium. It is possible that ventricular production of the peptide contributes to the raised circulating concentrations of atrial natriuretic peptide immunoreactivity found in severe congestive heart disease, particularly in patients with dilated cardiomyopathy.

Adolescent↗
PubMed1988

An electronic, negative feedback device to control arterial pressure.

Cardiovascular investigations frequently require manipulation of the arterial pressure for assessment of neural reflexes. This has largely been accomplished in the past by a bolus injection or constant infusion of a vasoactive drug. The purpose of the present investigation was to develop a proportional, integrative, negative feedback device capable of controlling arterial pressure in rats by modulating the infusion rate of the vasoconstrictor, phenylephrine. The device was designed to 1) maintain arterial pressure at a constant plateau level above the prevailing control pressure and 2) create linear ramp increases in arterial pressure. We have validated this system with conscious and urethan-anesthetized rats instrumented with arterial cannulas for arterial pressure measurement and aortic or venous cannulas for phenylephrine infusion. When used to create steady-state changes in blood pressure at 150 mmHg, the device maintained arterial pressure within +/- 7 mmHg of the desired level for the 20-min experimental periods. When used to create rising arterial pressure ramps (duration: 60 s; magnitude: 30 mmHg), regression analysis of the pressure vs. time relationship indicated that the correlation coefficient was greater than 0.99 in 90% of the trials, indicating a linear ramp. This device will aid in future cardiovascular protocols, especially in the analysis of baroreflex sensitivity.

Animals↗
PubMed1988

Doppler mapping of postoperative left atrioventricular valve regurgitation.

Left atrioventricular valve regurgitation often occurs as a postoperative hemodynamic complication from repair of an atrioventricular septal defect. In this study, cross-sectional two-dimensional Doppler flow mapping of the left atrium was used to quantify postoperative regurgitant flow in 29 patients. Its severity and location was related to the shape of the three leaflets of the left component of the atrioventricular valve, especially to the size of the mural leaflet. To identify which leaflet configuration was likely to cause regurgitation, the position of the leaflets was obtained from the parasternal short-axis view and the angular size of the mural leaflet expressed in degrees of an arc. Doppler mapping was performed in the apical four-chamber and the parasternal long-axis views, dividing the left atrium in nine squares in each. Regurgitation was defined as a jetlike systolic downstroke of the Doppler frequency shift in early systole. The angular size of the mural leaflet varied from 38 to 144 degrees (mean 86 +/- 36 SD). Massive regurgitation (six to nine sites) was encountered in seven patients, five with a mural leaflet size of over 110 degrees, one with mural leaflet size between 70 and 110 degrees, and one with a mural leaflet size of under 70 degrees. No or minimal regurgitation was encountered in 10 patients, three having a mural leaflet size of 70 to 110 degrees and seven with a mural leaflet size of less than 70 degrees. These data suggest that massive regurgitation is encountered in patients with large mural leaflets, whereas patients with smaller mural leaflets tend to have no or mild regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1988

Surgical treatment for double-outlet right ventricle at the Brompton Hospital, 1973 to 1986.

Between January 1973 and February 1986, operations were performed on 120 consecutive patients having usual atrial arrangement (atrial situs solitus), concordant atrioventricular connection, and double-outlet right ventricle. The ages at operation ranged from 1 day to 44 years and the weights from 2.6 to 84 kg. Sixty-three patients had one or more palliative procedures. For those, the hospital mortality rate was 9.5%. Palliation was considered a definitive procedure in 13 patients. Ninety-three patients had a reparative operation, with a 26.9% early mortality rate. In the group who had complete correction, taken as a whole, the surgical outcome was significantly affected by the position of the ventricular septal defect and by the year of operation. The year of operation was the main factor that, by multivariate analysis, correlated significantly with the hospital mortality in those patients having a subaortic defect and spiraling great arteries (p less than 0.05). No difference was found among this group for those patients having the morphologic characteristics of tetralogy of Fallot. The change-over point from the Mustard to the arterial switch procedures was the event with the greatest effect on hospital mortality in patients with a subpulmonary ventricular septal defect (p less than 0.025). Two late deaths have occurred among the 21 patients who had palliative intervention only. Sixty of the 68 survivors with intracardiac repair have been followed up for a period of 2 to 184 months (median 44 months). There were five late deaths (8.3%). Eight patients underwent successful reoperation. All except three of the long-term survivors were in functional class I. Good early and long-term results can be anticipated for the intracardiac repair of double-outlet right ventricle when the ventricular septal defect is subaortic or doubly committed. The arterial switch operation has been demonstrated to be the optimal approach for double-outlet right ventricle with subpulmonary ventricular septal defect. Results in patients with noncommitted ventricular septal defect have remained poor.

Adolescent↗
PubMed1988

Divided right atrium (prominence of the eustachian and thebesian valves).

Division of the morphologically left atrium (cor triatriatum) is a recognized clinical and surgical entity. Division of the right atrium (prominence of the eustachian and thebesian valves) is recognized pathologically, but is rare. It is unusual for this entity to be diagnosed during life. Stimulated by our experience with two patients seen at operation, one with an obstructive spinnaker-like formation and the other with a partitioned right atrium in the setting of pulmonary atresia, we reviewed the specimens in the heart museum of Children's Hospital of Pittsburgh that had prominence of the eustachian and thebesian valves. We identified 14 such hearts, which could be divided into two groups. In the first group, comprising six hearts, the valves were prominent in the form of Chiari networks and were of no functional significance. The valves were more extensive in the other eight hearts and partitioned the right atrium. In two of these, the valves themselves were the impediment to flow through the right side of the heart. In the other six, there was either atresia or severe stenosis along the right-sided pathways so that, after birth, the prominent valves retained their role during fetal life; namely, to deflect inferior caval venous return across the atrial septum to the left atrium. The partitions in these latter hearts would be of functional significance only if it were necessary to perform a Fontan procedure, when they might obstruct flow through an atriopulmonary (or atrioventricular) anastomosis.

Female↗
PubMed1988

Surgical management of doubly committed subarterial ventricular septal defects.

The clinical presentation, diagnosis, and surgical treatment of 63 patients with doubly committed subarterial ventricular septal defects (DCVSD) were analyzed retrospectively. The patients were divided into three groups. Thirty-one patients had severe congestive heart failure in infancy and presently have a large ventricular septal defect that has no tendency to close or to produce aortic valve regurgitation (Group 1). Ideally, these defects should be closed in infancy, and the transpulmonary approach is recommended to achieve closure. In the first group, there was one death in a patient with a hypoplastic right ventricle. In Group 2, nineteen patients had aortic valve prolapse or aortic valve regurgitation. The DCVSD were moderately large or small. A number of DCVSD in Group 2 patients had maintained the normal offsetting of the arterial valves. These defects must be closed by the time mild aortic valve regurgitation has occurred. In Group 2, there was one late death in a patient who developed subacute bacterial endocarditis. The two patients who had severe aortic valve regurgitation required aortic valve replacement and underwent multiple surgical procedures to replace calcified bioprostheses. Group 3 comprised 13 patients who were diagnosed with tetralogy of Fallot. All of these patients had a large DCVSD with aortic valve overriding. All Group 3 patients survived radical repair of the defect, which required a transannular patch in most cases (76%).

Adolescent↗
PubMed1988

The arterial supply to the right atrium and the sinus node in classic tricuspid atresia.

Dissection was performed in 41 hearts from patients with classic tricuspid atresia so as to demonstrate the major arteries supplying the right atrium and the sinus node. A right anterior atrial artery was identified in 85.4% of the hearts, a right lateral atrial artery was seen in 68.3%, a right posterior atrial artery in 41.5%, and a left anterior atrial artery in 78.0% of the specimens. The artery to the sinus node, identified in 34 hearts, originated from the right coronary artery in 38% of the cases, from the left coronary artery in 59%, and had a dual origin in 3% of cases. The relative importance of these arteries is discussed with regard to the atriopulmonary anastomosis of the Fontan procedure. Special consideration is given to the incisions employed in different variations of this operation and the arterial distribution is compared to that found in the normal heart.

Coronary Vessel Anomalies↗
PubMed1987

Identification and analysis of left atrial isomerism.

The veno-atrial connections, atrial morphology, atrioventricular (AV) junction, ventricular mass, ventriculoarterial (VA) connection and great arteries in 22 autopsied hearts, diagnosed as having bilateral left-sidedness because of the morphology of the atrial appendages, were studied. The findings were correlated with the arrangement of the thoracic-abdominal organs. A solitary spleen was found in 3 and double spleens in 2 hearts (the remaining 17 hearts had multiple spleens) but left bronchial isomerism existed in all hearts in which bronchial arrangement could be determined. The heart was in the left chest in 14 cases, in the right chest in 5 and midline in 3. The apex pointed to the left in 18 hearts while in 4 hearts it pointed to the right. Fifteen hearts had a biventricular and ambiguous AV connection, 3 hearts had an absent left AV connection and 4 had double-inlet connection via a common valve (to the left ventricle in 3 and the right ventricle in 1). The VA connection was concordant in 14 hearts, discordant in 1, double outlet from the right ventricle in 4, double outlet from a solitary indeterminate ventricle in 1 and single outlet from the right ventricle through a pulmonary trunk with aortic atresia in 2 hearts. Superior caval veins were present bilaterally in 13 hearts. There was interruption of the infrahepatic inferior caval vein with azygos or hemiazygos continuation in 19 hearts while in 3 hearts the inferior caval vein continued upwards to drain into the right-sided morphologically left atrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1987

The effects of bilateral and unilateral frontal lesions on visual cortical hypersynchronous bursting and behavioral activity.

Photically evoked after-discharge (PhAD) bursting was examined in albino rats following either bilateral or unilateral dorsal frontal lesions. The initial effect of either type of frontal lesion was to significantly suppress PhAD occurrence. However, after repeated exposure to the PhAD recording environment no difference could be seen between the lesioned and control animals. In addition, no difference in PhAD could be detected between the two visual cortices in any of the groups. Spontaneous alternation and open-field activity were also tested. Both frontally lesioned groups of animals were significantly more active than control animals in the initial stages of testing. These findings indicate that the frontal cortex can inhibit brain stem mechanisms which are responsible for behavioral arousal and the modulation of hypersynchronous bursting in the cortex. However, because no difference was seen between the two visual cortices in any of the groups, it is suggested that this mechanism is not a strictly unilateral mechanism.

Animals↗