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Biomedical subjects

P Arnsbo

Publications and source records attributed to P Arnsbo.

11 recordsLinked to original sources
PubMed1991

[Does alternative medical equipment result in pacemaker dysfunction?].

Employment of alternative therapeutic measures is increasing in Denmark. Some of this equipment employs magnetic fields in the therapeutic strategy. This may involve interference with the function of electronic equipment. Electronic interference may, in certain situations, influence pace-maker function. In the worst cases, it may be imagined that the situation may endanger life for persons who are dependent on pace-makers. When a pace-maker is exposed to a magnetic field of a certain strength, the type of pacing is changed to a fixed frequency. Some pace-maker types carry out a built-in test programme when exposed to magnetic influence (vario- or threshold test). The magnetic influence may involve discomfort for the wearer of the pace-maker, but does not endanger life. Investigation of stationary magnetic fields from alternative medical equipment resulted in disturbance of pace-maker function in an isolated case. Pulsating magnetic fields may result in possible induction of electric current which may be wrongly interpreted by the pacemaker. The results of this may be that the pace-maker does not send out pace impulses. As protection from continuous electric noise, pace-makers have a built-in electronic safety circuit (dual-demand). When this is activated, the pace-maker will stimulate with a basic frequency. It is recommended that equipment which employs magnetic fields in treatment should be measured before being employed on pace-maker wearers.

Complementary Therapies↗
PubMed1991

[Placing of implantable devices for electric stimulation].

Various electrical devices are implanted for cardiac-, diaphragma-, pain- and musclestimulation. The stimulator/pacemaker can be implanted in locations, different from that of ordinary cardiac pacemakers. All electric stimulation equipment containing batteries must be removed before cremation on account of the risk of explosion.

Aged↗
PubMed1991

The epidemiology of pacemaker implantations in Fyn county, Denmark.

Throughout the last three decades the number of patients with pacemakers has increased. Registers of pacemakers and pacemaker patients have been established to monitor, for example, the battery life expectancy and patient data. We have analyzed the registry for Fyn county, Denmark, which includes data on incidence, prevalence, and mortality rates among patients with pacemakers during the period from 1964 to 1990. The analyses show that the prevalence rate is steadily increasing as a result of a combination of an increasing incidence rate and a stable mortality rate among the pacemaker patients. Based on the development in the first almost 30 years of pacemaker implantations, two trends of the future prevalence of pacemaker patients are projected. Provided constant mortality rates and expected incidence rates of 300 per million person years and 350 per million person years, respectively, the prevalence will reach a plateau of 2.7 per 1,000 persons and 3.1 per 1,000 persons, respectively, within the next 25 years.

Denmark↗
PubMed1989

Pregnancy and cesarean section in a patient with a rate-responsive pacemaker.

The function of a rate-responsive pacemaker was monitored during pregnancy and cesarean section in a woman with complete atrioventricular block. The observations during pregnancy were compared to similar observations obtained in a pregnant normal woman of comparable age, height and weight, and in 12 normal women during elective cesarean section. During pregnancy, the heart rate increased in the normal woman, whereas the pacing rate in the woman with the implanted pacemaker was unchanged. Fetal movement caused an increase in pacing rate in the 37th week of gestation, whereas the heart rate in the normal woman did not respond. During cesarean section the pacing rate was generally within the mean +/- 1 SD for normal women.

Adult↗
PubMed1986

Superiority of multiprogrammable to nonprogrammable VVI pacing: a comparative study with special reference to management of pacing system malfunctions.

Analysis of pacing system malfunctions was performed in 374 patients at initial implantation or at pulse generator and lead replacement during a period of 55 months. A total of 150 nonprogrammable pacemakers were implanted in 148 patients, while 236 multiprogrammable pacemakers were implanted in 226 patients. The purpose of the analysis was to investigate the occurrence and management of malfunction unrelated to pacemaker/lead failure or lead dislodgement. The nonprogrammable group was followed for 3-53 months (median, 36). Malfunction occurred in 18 patients (12.0%): muscle stimulation in 14; exit block in three; sensing problem in one. Surgical correction was necessary in 14 of 18 cases. The multiprogrammable group was followed for 3-52 months (median, 12). Malfunction occurred in 30 cases (12.7%): muscle stimulation in 22; threshold increase in seven; sensing problem in one. Only seven of these patients required surgical correction as 23 cases were successfully managed by reprogramming alone. Malfunctions occurred during a period of several days to 36 months (median, 2.3 months). The difference in rate of secondary surgical intervention was significant (p less than 0.01). Measurements during reoperation in the nonprogrammable group showed that at least 40% of late malfunctions would have been correctable by reprogramming alone. Thus, multiprogrammability is of significant value for noninvasive correction of malfunctions unrelated to pacemaker and lead failures, predominantly muscle stimulation and threshold elevation.

Aged↗
PubMed1979

Measurements of cardiac stroke volume in various body positions in pregnancy and during Caesarean section: a comparison between thermodilution and impedance cardiography.

A total of 220 simultaneous pairs of measurements of cardiac stroke volume were made in twelve women before and during Caesarean section in order to compare impedance cardiography with the thermodilution method. A significantly higher coefficient of correlation was found before (r = 0.77) than during anaesthesia (r = 0.55). Further, there was a significant difference in the slope of the regression lines: before anaesthesia the slope was 1.07 and during anaesthesia with thiopentone, nitrous oxide, oxygen and suxamethonium it was 0.45. Significant changes in the intercept on the Y-axis were found before (-13.9 ml) and during anaesthesia (33.4 ml). When the uterus was displaced upwards and to the left from the 15 degrees tilt position the stroke volume and the cardiac output were increased when measured by both methods to nearly the same values as in the left lateral position. It is concluded that the impedance method is reliable for measuring cardiac stroke volume in late pregnancy under physiological conditions in the conscious patient, but that it cannot replace the thermodilution method in pharmacological studies.

Adult↗
PubMed1978

Haemodynamic effects of oxytocin (syntocinon) and methyl ergometrine (methergin) on the systemic and pulmonary circulations of pregnant anaesthetized women.

The haemodynamic effects of oxytocin (Syntocinon) and methyl ergometrin (Methergin) were studied in 9 healthy females in the first trimester of pregnancy. The patients were anaesthetized with sodium thiomebumal, pethidine and pancuronium bromide and ventilated on a Manley respirator. 10 i.u. oxytocin given as an i.v. bolus brought about a fall in femoral arterial pressure of 40%, systemic resistance 59% and pulmonary resistance 44% 30 sec after injection. However, the heart rate increased 31% and stroke volume 17%, so that the cardiac output increased by 54%. The pulmonary arterial pressure and wedge pressure were increased by 33% and 35%, respectively 150 sec after injection. No changes were seen in the haemodynamic parameters during infusion of 80 mU oxytocin for 10 min. 0.2 mg Methergin brought about an increase in the femoral arterial pressure of 11%, pulmonary arterial pressure 27% and wedge pressure 31%, with no changes in the other measured parameters. The use of oxytocic drugs in patients with compromised circulation is discussed.

Adult↗
PubMed1977

Measurement of rapid changes in cardiac stroke volume. An evaluation of the impedance cardiography method.

One hundred and twenty-nine simultaneous measurements were carried out on seven patients, 67 at rest and 62 during the Valsalva manoeuvre, in order to compare impedance cardiography with the thermodilution method, during rapid changes in cardiac stroke volume and pulmonary blood volume. A coefficient of correlation of 0.86 was found following linear regression analysis of the whole material. Analysis of the individual patient showed that the mean coefficient of correlation was 0.94 (range 0.91-0.97), and that the slope of the regression lines was 0.41 to 1.82, and further that the mean intercept was 0.2 ml. It is concluded that impedance cardiography can be employed for measuring the relative intraindividual changes in cardiac stroke volume during the Valsalva manoeuvre, and it is suggested that it may be of use in other situations, such as during haemorrhage or continuous positive pressure ventilation.

Adolescent↗