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Biomedical subjects

H Netz

Publications and source records attributed to H Netz.

At least 55 records · Page 3Linked to original sources
PubMed1981

Actively adhering endocardial leads for pacing in children.

Cardiac pacing in children still presents problems concerning the most favorable placement of the generator and, in particular, the growth-induced electrode complications. Whereas in infants epicardial implantation is unavoidable, one would prefer transvenous placement in older children to permit replacement or removal without extensive operative measures. The use of actively anchorable endocardial leads seems advantageous because of the possibility of placing long electrode loops in the cavity of the right atrium without increasing the risk of dislodgement. In this way overextension of the lead during growth may be avoided. Since June 1975 we have performed ventricular pacing in 10 children, aged 2 to 9 years, by using a transvenous screw-in electrode (surface 6 mm2). Acute threshold values ranged from 0.4 to 0.7 mA ap a pulse duration of 1.0 msec and sensitivity between 6.5 and 8.7 mV. Electrode function has been without complications up to now. In 6 patients we implanted programmable pacemaker systems which allowed postoperative threshold measurements. The chronic threshold value has not increased above 2.3 mA in any of these cases. In our opinion, actively anchorable endocardial leads present significant advantages for pacing in childhood.

Child↗
PubMed1980

Ventricular self-defibrillation in mammals: age and drug dependence.

Ventricular fibrillation (VF) was electrically induced in cats, rabbits, guinea pigs and rats. In young animals of all species and also in old rats short transient VF (TVF) was followed by spontaneous reversion to normal sinus rhythm. Old cats, rabbits and guinea pigs had episodes of sustained VF (SVF) which did not terminate spontaneously; artificial electro-defibrillation was required. Dibenzepin converted the sustained response of old animals to a transient one. Verapamil antagonized the effect of dibenzepin in old animals and also changed the TVF in young animals to SVF. The effect of calcie age of the animal is an important factor in determining whether the fibrillatory red to an alteration in the properties of the cell membrane.

Aging↗
PubMed1980

[Pharmacokinetic analysis of the fluctuation in digitalis bloodlevels during oral therapy with beta-methyldigoxin in children with heart insufficiency (author's transl)].

In five children with insufficiency of the heart the blood digitalis-digoxin level was monitored by drawing blood 5 times daily over a period of 7 days, starting from the first day of digitalisation. The dosage aimed at a mid-rate attainment of the plateau concentration in the blood. Digitalis blood levels were determined by a commercial radioimmunoassay. The blood level curves were simultaneously adjusted over the whole period, with the aid of a self-developed programme for tablecacultators, so that the considerable fluctuations of blood levels could be exhibited. The so adjusted curves were also pharmacokinetically analysed. Our data are in good agreement with the literature. The total clearance was significantly below that of adults. The total amount of digoxin in the whole organism, as calculated and represented graphically, changed less significantly, but was clearly higher in the first days of the mid-rate digitalisation than during the steady state.

Administration, Oral↗
PubMed1980

[Problems in pacemaker therapy in childhood (author's transl)].

Over a period of 10 years, 16 children, aged 1.8 to 13 years underwent implantation of a cardiac pacemaker. The most common indication, in 11 cases, was a complete post-operative heart blockage. Two children died without it being able to be ascertained whether the pacemaker had in fact failed. There was a return of sinus rhythm in the case of 4 children. Pacemaker therapy over a period of 56 patient years produced 19 cases with such severe complications that renewed surgical treatment was necessary.

Adolescent↗
PubMed1979

Dibenzepin as an antifibrillatory agent for spontaneously terminating electrically induced ventricular fibrillation.

The effect of dibenzepin, a tricyclic antidepressant drug, on electrically induced ventricular fibrillation was studied in 20 cats and nine dogs. The ventricular fibrillation threshold and the ability of the ventricle to defibrillate spontaneously were determined before and after the administration of dibenzepin, with each animal serving as its own control. The drug raised the ventricular fibrillation threshold in all the animals tested. Before treatment, spontaneous ventricular defibrillation occurred in only 8 of the 20 cats and in none of the dogs. After treatment, all of the cats and eight of the dogs exhibited spontaneous ventricular defibrillation. The study of drugs that have a self-defibrillatory effect may serve to further understanding of the mechanism of ventricular fibrillation and its spontaneous termination.

Animals↗
PubMed1979

[Treatment of a severe temporary heart arrhythmia by transvenous pacing in a neonate (author's transl)].

Report of the treatment of a neonate with bradycardia (cardiac dysrhythmia) with an external transvenous pacemaker. At the age of 19 days the child developed repeated and critical dysrhythmias which made intubation and artificial respiration necessary. Conservative therapy attempts were without success. A stimulation-catheter was inserted through the internal jugularis vein and an external Demand-pacemaker connected to it. The stimulation-catheter was disconnected after 12 days with the complete cessation of the initial frequent bradycardia episodes. The cause of the cardiac dysrhythmia could not be clearly found. Tachycardia-bradycardia syndrome and Phase-IV block are being discussed.

Bradycardia↗
PubMed1978

[Treatment of intractable diarrhea in infancy with human milk (author's transl)].

Progressive, severe diarrhea in a Turkish infant, beginning at age of 6 weeks, was refractory to conventional therapy, including casein hydrolysate and total parenteral nutrition. At age of 9 months, human milk as sole food together with small doses of prednisone was started. During the next 7 months of feeding human milk, body weight of the infant rose from 4750 to 7000 g and the stools became normal.

Diarrhea, Infantile↗
PubMed1977

Behavior of blood acetaldehyde in alcohol-treated rats following administration of thiurams.

Single moderate doses of Na-dimethyldithiocarbamate and Na-diethyldithiocarbamate (thiocarb), respectively, did not influence the rate of elimination of ethanol i.p. in female rats, but there was a concurrent substantial increase in the blood acetaldehyde content. Tetramethylthiuram disulfide (thiram) produced a slight decrease in the rate of elimination of ethanol, while a comparable dose of tetramethylthiuram disulfide (disulfiram) failed to affect ethanol disappearance. At the same time, the blood acetaldehyde concentration showed a considerable increase which after thiram was much more significant than after disulfiram, Identical thiuram doses caused a significant reduction in the rate of elimination of acetaldehyde i.v., which suggests an inhibition of the aldehyde dehydrogenasel aldehyde oxidase and helps to explain the elevated blood acetaldehyde concentration which was observed in the presence of ethanol. It is concluded from these findings that thiuram activity decreases as the number of carbon atoms at the side-chains of the molecule is increasing.

Acetaldehyde↗
PubMed1977

[Non-rheumatic carditis. A diagnostic study in a period of 11 years (author's transl)].

23 paediatric cases of non-rheumatic carditis seen in the period between 1965 and 1976 are reviewed. Neonatal carditis is very letal, but the prognosis improves with increasing age. Males and females are equally affected. There is a rise in frequency since 1971. 9 of the 23 cases ended letally. In further 9 cases congenital heart lesions occurred simultaneously, 3 of which were ventricle septal defects. The most important diagnostic feature is the cardiac enlargement (94% of our cases). Other important signs and symptoms are dyspnoea at rest tachycardia and fever. The ECG changes (89%) are non-specific. Very often, it is not possible to classify the disease into endo-, myo- or pericarditis; the term "carditis" is, therefore, preferred. Virological and bacteriological findings were found in only 35% of the cases.

Age Factors↗