Search PubMed⌕ Search

Biomedical subjects

M J Tynan

Publications and source records attributed to M J Tynan.

At least 37 records · Page 2Linked to original sources
PubMed1985

Embolisation procedures in congenital heart disease.

Eight therapeutic embolisation procedures were performed by the transcutaneous catheter technique in seven patients with congenital heart disease. After surgical correction of tetralogy of Fallot (four patients), catheter embolisation was used to occlude two large aortopulmonary collaterals (one patient), three small aortopulmonary collaterals (one patient), and two Blalock-Taussig shunts (two patients). In two patients congenital coronary anomalies were occluded--a coronary arteriovenous malformation and a coronary artery/bronchial artery anastomosis. In one patient a pulmonary arteriovenous malformation was embolised. Detachable balloons were used to occlude six large arteries, the three small arteries were occluded with small gelfoam fragments, and the pulmonary arteriovenous malformation was occluded with multiple steel coils and large gelfoam pieces. Successful occlusion was achieved in all cases. No complications were encountered and the procedure was well tolerated even in the two patients receiving postoperative intensive care. Therapeutic embolisation in suitable cases is a safe and effective alternative to surgery and the detachable balloon technique is effective in occluding high flow vessels.

Adolescent↗
PubMed1984

Radionuclide measurement of left ventricular ejection fraction in infants and children.

The left ventricular ejection fraction was measured in 60 infants and children with congenital heart disease by both the equilibrium gated radionuclide technique and biplane left ventricular cineangiography. The median age of the patients studied was 2.25 years, and 17 were less than 1 year old. The correlation coefficient for the two sets of measurements was good and did not deteriorate in subgroups under 1 year old and with a large left to right shunt. In those infants with a right to left shunt the correlation was weak. Equilibrium gated radionuclide angiography is a valid and clinically valuable method of measuring left ventricular function in infants and children with congenital heart disease.

Adolescent↗
PubMed1984

Balloon atrial septostomy in the neonatal intensive care unit.

In eight infants with complete transposition of the great arteries balloon atrial septostomy was performed in the neonatal intensive care unit solely under cross sectional echocardiographic control. One infant developed necrotising enterocolitis; otherwise there were no complications. This technique eliminates the need for radiographic screening during the procedure, is quick, and causes little disturbance to the infant who does not have to be removed from the incubator.

Echocardiography↗
PubMed1984

Use of radionuclide labelled microspheres to show the distribution of the pulmonary perfusion with multifocal pulmonary blood supply.

In pulmonary atresia with a ventricular septal defect and similar congenital heart disorders the pulmonary blood supply is often multifocal. The relative distribution of pulmonary perfusion from individual sources is usually demonstrated by selective angiography. A new technique using a selective injection of radionuclide labelled human albumin microspheres was performed in four patients with a complex pulmonary blood supply. In these cases the physiological distribution of each of the multiple sources of pulmonary perfusion was demonstrated. This is a useful additional technique in the assessment of such patients.

Adolescent↗
PubMed1984

Echocardiographic and anatomical correlations in fetal congenital heart disease.

In a series of 1600 pregnancies 34 cases of congenital heart disease were correctly identified by fetal echocardiography. In each case echocardiographic diagnosis was confirmed by anatomical study. Termination of pregnancy was done electively in 14 cases: in six because of the identification of a cardiac anomaly and in the remaining eight because of multiple congenital anomalies. The remaining 20 fetuses died subsequently owing either to the complexity of congenital heart disease or to associated extracardiac abnormalities, which were present in more than half the fetuses with congenital heart disease. There were eight errors in interpretation of the fetal echocardiogram. The outcome of the pregnancy was not influenced by the error in any case. Fetal echocardiography can predict correctly structural malformations of the heart. The technique is sufficiently reliable to give an accurate prognosis in early pregnancy and provide the basis for alterations in obstetric management.

Diagnostic Errors↗
PubMed1984

Radionuclide measurement of left ventricular ejection fraction in tricuspid atresia.

In 15 patients with tricuspid atresia and one with tricuspid stenosis the left ventricular ejection fraction was measured by equilibrium gated radionuclide angiography and the results compared with those from a control group of 16 patients. The patients with tricuspid atresia had a significantly depressed ejection fraction. Those who had a surgical shunt or who had had pulmonary artery banding had significantly lower ejection fractions than the remainder. There was no significant correlation between the ejection fraction and age, the arterial oxygen saturation, or the haemoglobin concentration. Five patients were also studied during isometric exercise; three had an abnormal response. Volume overload of the ventricle is identified as one cause of the dysfunction, but other factors may be important. Radionuclide angiography offers a non-invasive method of studying ventricular function in this condition.

Adolescent↗
PubMed1980

Echocardiographic and anatomical correlates in the fetus.

Fetal cardiac anatomy was studied in 200 pregnancies between 14 weeks' gestation and term using real time two-dimensional echocardiography. Eight scan planes were chosen as contributing valuable and distinct information on the establishment of cardiac normality. To confirm the echocardiographic interpretation, 25 fetal specimens between 12 and 28 weeks' gestational age were sectioned to imitate echocardiographic scan planes and the echocardiographic and anatomical pictures obtained were correlated with each other. The number of patients in whom each plane was recognized was tabulated in the first and second hundred, the second hundred having been studied after the anatomical studies were made. One longitudinal and one transverse plane could be seen in nearly all patients and considerable improvement in the frequency of recognition of other planes was made in the second hundred patients with increasing experience and anatomical understanding. The tricuspid-pulmonary and four-chamber planes alone, however, showed four cardiac chambers, two atrioventricular valves, and two arterial valves within their respective outflow tracts.

Echocardiography↗
PubMed1979

Nomenclature and classification of congenital heart disease.

At present there is no universally accepted nomenclature for congenital cardiac malformations. Much of the controversy results from failure to distinguish the structural connections of the heart from the morphology and spatial relations of its components. The confusion is compounded by an abundance of individual definitions, many of them speculative. The present article proposes a totally descriptive nomenclature. It describes in turn the connections of the cardiac segments, their morphology, their relations, and additional anomalies in any segment. Each step in the segmental approach is discrete. The overall effect is to force a succinct and comprehensive description of any cardiac malformation, no matter how complex.

Coronary Vessels↗
PubMed1977

Postnatal ultrastructural changes in the cat myocardium: a morphometric study.

In order to understand more clearly the basis for our previously observed postnatal age related changes in the mechanical performance of the cat myocardium we have carried out a quantitative ultrastructural analysis of right ventricular papillary muscles obtained from adult cats (1.8 to 2.3 kg), infant cats (16 days of age), and neonatal kittens (less than 72 hours old). Volume fractions were calculated for myofibrils, sarcoplasm, mitochondria, lipid, sarcoplasmic reticulum (SR), golgi, and nuclei. The myofibril content of neonatal fibres was significantly less than that of the infant or adult groups (P less than 0.05 and 0.005 respectively). In addition the infant fibres contained a smaller volume of myofibrils than the adult ones (P less than 0.001). The mitochondrial content of the neonatal fibres was also significantly less than that of either the infants' (P less than 0.005) or adults' (P less than 0.001). These data provide an anatomical basis for the progressive age related increase in mechanical performance of the cat myocardium, in postnatal life.

Animals↗