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Biomedical subjects

H Netz

Publications and source records attributed to H Netz.

At least 37 records · Page 2Linked to original sources
PubMed1994

Heart-lung transplantation in a patient with pulmonary atresia and ventricular septal defect.

Operation for pulmonary atresia and ventricular septal defect is challenging, as in most patients the pulmonary arteries are hypoplastic, nonconfluent, or in part absent. In these cases, combined heart-lung transplantation may be the surgical treatment of choice. In the described case, the morphology of pulmonary atresia and ventricular septal defect was present in combination with completely atretic main, left, and right pulmonary arteries. In this patient, successful heart-lung transplantation was performed.

Adult↗
PubMed1993

Distribution of myocardial beta-adrenoceptor subtypes and coupling to the adenylate cyclase in children with congenital heart disease and implications for treatment.

In congestive heart failure, down-regulation of myocardial beta-adrenoceptors (beta-AR) due to an elevated sympathetic tone is well known. In infancy and childhood, heart failure is usually related to congenital heart disease (CHD). Therefore, 71 samples of right atrial tissue of infants and children with CHD undergoing cardiac surgery were studied for beta-adrenoceptor density and distribution of the beta 1-/beta 2-AR subtypes. In 49 cases, the coupling of the beta-AR to the adenylate cyclase (AC) was examined. In a further study of 19 myocardial samples, AC was selectively stimulated with beta 1- or beta 2-AR whereas the other subtype was blocked by an antagonist. The following results were obtained: (1) Infants and children with severe acyanotic or cyanotic CHD had severely reduced beta-AR densities. (2) In most of the cases, the beta-AR down regulation is beta 1-subtype selective, but in critically ill newborns with congenital aortic valve stenosis or transposition of the great arteries, there is additional significant beta 2-AR down-regulation. In Fallot patients treated with the beta-antagonist propranolol, a significant increased beta-AR number compared with untreated Fallot patients was found. (3) beta-Adrenoceptor reduction in CHD is correlated with elevated noradrenaline plasma levels, thus proving a sympathetic dysregulation. (4) In CHD with moderate hemodynamic load, beta 2-AR coupling to AC was markedly more efficient than beta 1-AR coupling. The small number of myocardial beta 2-AR produced most of the cyclic adenosine monophosphate. (5) In severe acyanotic and cyanotic CHD, a partial decoupling of the beta 2-AR to the AC occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1993

Heart transplantation after Senning operation for transposition of the great arteries.

In a 17.5-year-old boy and a 21-month-old girl orthotopic heart transplantation was performed after intractable right-heart failure had developed 14.5 years and 15 months respectively after Senning operation for TGA. Before the atrial repair, combined with closure of the VSD in each case, initial operation had involved a banding of the pulmonary artery in the boy and a modified Blalock-Taussig shunt in the girl. A coarctation of the first patient remained untreated. After resection of the diseased organ a new intraatrial septum of glutaraldehyde-fixed bovine pericardium was created. 15 and 3 months respectively after orthotopic heart transplantation both patients belong to NYHA classification I.

Adolescent↗
PubMed1992

[Surgical therapy of congenital cardiovascular abnormalities. Palliation, correction, transplantation].

Thanks to new and further developments of surgical procedures, it has now become possible to provide surgical treatment for any form of congenital heart defect. For some procedures, however, long-term results are not yet available. In this review, currently accepted basic principles of modern surgical treatment of congenital heart disease are discussed. On the basis of the most common anomalies, the various surgical techniques (palliation, correction and heart transplantation) are considered.

Heart Defects, Congenital↗
PubMed1992

[Incidence, prevention and therapy of cytomegalovirus and pneumocystis carinii infection after heart transplantation].

Diseases caused by cytomegalovirus (CMV) and pneumonia due to pneumocytis carinii (PCP) are problematic complications after allogeneic heart transplantation. Recipients of CMV-seropositive donors have a higher morbidity of CMV. By using an anti-CMV-immunoglobulin preparation in routine prophylaxis the incidence of CMV disease after heart transplantation could be reduced significantly. Ganciclovir 10 mg/kg is administered for treatment of CMV disease for at least 14 days. Recent investigations show that a prophylactic administration of ganciclovir after heart transplantation is safe, and it reduces the incidence of CMV-induced illness in CMV-seropositive patients. The incidence of PCP after heart transplantation varies according to the literature between 1 and 13%. The onset of the disease is located mostly between the third and the fifth month after heart transplantation. An effective prophylaxis can be achieved by low dose cotrimoxazole (960 mg at two days per week in adults) within the first six postoperative months. Cases of PCP are treated by cotrimoxazole or pentamidine and are associated with a mortality up to 60%.

Antibodies, Fungal↗
PubMed1991

Pediatric heart transplantation for congenital heart disease and cardiomyopathy.

Orthotopic heart transplantation has become an accepted therapy for adult patients with end-stage heart disease. In newborns and infants, this procedure is still controversial because of the unknown long-term results and the lack of donor organs. Since March 1988, we have performed orthotopic heart transplantation in 11 infants and children with hypoplastic left heart syndrome (n = 6), cardiomyopathy (n = 4), or congenital endocardial fibroelastosis (n = 1). The smallest infant was 3 days old and weighed 2,650 g. Four of 15 potential donors had to be refused for various medical reasons, and 4 were transferred to our hospital for organ retrieval. Seven hearts were procured remotely. We accepted weight mismatches up to 105% between donor and recipient. There were three perioperative deaths, two in patients 5 and 17 days old with hypoplastic left heart syndrome and 1 in a 2-year-old patient with a dilated cardiomyopathy. All 3 patients had drug-resistant right heart failure. A 2-year-old girl with a dilated cardiomyopathy died 2 months after transplantation owing to severe pulmonary embolism originating from the superior vena cava. The remaining 7 patients are alive and well between 1 month and 31 months after transplantation. Angiographic follow-up has not revealed signs of graft atherosclerosis at 2 years.

Cardiomyopathy, Dilated↗
PubMed1990

Cardiac transplantation in a neonate with endocardial fibroelastosis.

An investigational orthotopic cardiac transplantation was performed to manage subendocardial fibroelastosis in a neonate. No unmanageable technical complications arose from the transplantation. Postoperative observation showed the infant developed normally except for moderate cerebral palsy.

Journal Article↗
PubMed1987

Reduction of infarct size following acute coronary occlusion by augmenting collateral blood supply induced by infusion of tricyclic antidepressants.

Previously, it has been shown that following occlusion of the left anterior descending artery (LAD) in cats, i.v. administration of tricyclic antidepressants (TCAD) significantly decreases the incidence of ventricular fibrillation (VF), which terminates spontaneously upon appearance. Furthermore, this treatment significantly decreases the size of the unperfused ventricular muscle (ischemic myocardium) from 44%-84% (mean 61%) to 17%-56% (mean 34%). This latter effect was demonstrated by using color demarcation of the perfused myocardium with the injection of a dye into the left atrium after 2 h of LAD occlusion in both control and treated cats. It was assumed that reduction of the unperfused area was due to an increase of collateral blood supply to the ischemic area. Although the beneficial effect of TCAD on the collateral blood supply has been clearly demonstrated in cats randomly assigned to two groups, the present study was designed to investigate the changes in the size of the ischemic area in the same animal by using two different dyes. Both dyes were injected into the left auricle after the LAD occlusion: The first was injected before the TCAD treatment and the second after the treatment. Two days after fixation in 4% formaldehyde, the hearts were sliced into three or four transverse sections. Examination of the sections indicated that there were three types of myocardial markings: (a) totally unperfused myocardium; (b) an area perfused by both colors; (c) an area perfused only by the second dye, indicating an increased collateral blood supply, the effectiveness of which was increased by the TCAD treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Heparinization during percutaneous cardiac catheterization in children.

The effect of heparin on blood clotting was studied by measuring the activated clotting time (ACT) in 120 infants and children with congenital heart disease after a single intravenous bolus of 100 IU heparin/kg body weight. Before heparinization, infants and children with cyanotic heart disease showed signs of hypocoagulation. Heparin bolus led to a threefold increase of ACT after 15 min. After 1 h, the ACT was still two times the normal value. Any further administration of heparin may be based on ACT monitoring.

Blood Coagulation↗
PubMed1987

[Measuring oxygen consumption in healthy infants and children and infants and children with heart diseases].

Oxygen consumption (VO2) must be known to calculate the hemodynamic parameters by Fick's principle. Often VO2 is not measured directly but calculated by nomograms. An open-system method was used for measuring oxygen consumption continuously in 140 healthy infants and children and 152 with congenital heart disease. The patients with heart disease were divided in three groups: I - with large left-to-right shunt (more than 40%), II - with a small left-to-right shunt, and III - without left-to-right shunt. In group I a significantly higher oxygen consumption was measured. There was also a difference in relation of indexed oxygen consumption to age between group I and all the other children. In a second part we compared two methods for determination of indexed oxygen consumption (VO2) in infants and children: measurement using an open system method estimation by using formulas. In healthy infants estimation showed higher values; but no difference was found in healthy children or those without significant left-to-right shunt. In children with congenital heart disease and large left-to-right shunt measured VO2 was significantly higher than the estimated values. No correlation was found in infants with large left-to-right shunt. But in these cases the exact calculation of the hemodynamic parameters would be of great importance. The results indicate that measurement rather than estimation of VO2 is necessary for calculation of hemodynamic parameters.

Child↗
PubMed1986

The effect of tricyclic antidepressants on ventricular fibrillation and collateral blood supply following acute coronary occlusion.

In previous studies, we showed that dibenzepin HCl (D) and other tricyclic antidepressants (TCAD), given either before or during occlusion of the left anterior descending artery (LAD), decreased the incidence of ventricular fibrillation (VF) following occlusion and reperfusion. Moreover, once VF develops in treated animals, it changes into a transient type, reverting spontaneously to a sinus rhythm. In the treated cats, retrograde perfusion of the occluded coronary artery was observed, most likely as a result of increased collateral blood flow. This latter effect is the subject of the present study. The LAD was occluded at its origin in 43 cats, 28 of which were treated either with D or with 5-iminodibenzyl HCl; the remaining 15 were untreated controls. Two hours after the occlusion, methylene blue was injected into the left atrium to determine color demarcation between the perfused and unperfused myocardium, and the cat was then killed. After fixing for 2 or 3 days in 4% formaldehyde, the hearts were sectioned transversely. The results showed that in the 15 control cats, the blood-supplied (blue) area ranged between 16% and 56% of the left ventricular muscle (mean 39%), while in the 28 treated cats the blue area was between 44% and 83% (mean 66%). These results clearly indicate the beneficial effect of TCAD on the blood supply of the occluded area and can explain, in part, the ability of these drugs to prevent VF even if infused after the coronary occlusion, and their protective effect against VF following reperfusion. No other antiarrhythmic drugs have been shown to possess this latter action.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗