Biomedical subjects

Rolf Hörnsten

Publications and source records attributed to Rolf Hörnsten.

6 recordsLinked to original sources

PubMed2007

Changes in heart rate variability among RF plastic sealer operators.

In a previous study, we showed that operators of radiofrequency (RF) plastic sealers, RF operators (n = 35) had a lower heart rate during nighttime compared to a control group (n = 37). We have analyzed the heart rate variability (HRV) on the same group of people to better understand the possible underlying rhythm disturbances. We found a significantly increased total HRV and very low frequency (VLF) power during nighttime among the RF operators compared to a control group. Together with our previous finding of a significantly lower heart rate during nighttime among the RF operators compared to the controls, this finding indicates a relative increase in parasympathetic cardiac modulation in RF operators. This could in turn be due to an adaptation of the thermoregulatory system and the cardiac autonomic modulation to a long-term low-level thermal exposure in the RF operators.

Adult↗

PubMed2005

Ventricular late potentials in familial amyloidotic polyneuropathy.

We investigated the occurrence of ventricular late potentials (LPs) in patients with familial amyloidotic polyneuropathy (FAP) and the possible association with ventricular arrhythmia on Holter electrocardiography and echocardiographic data. Fifty-five patients and 94 healthy controls were studied. LP were found in 46% of the FAP patients older than 60 years and in 15% of the controls (P = .02), whereas no difference was found in individuals younger than 60 years. The occurrence of LP was associated with nonsustained ventricular arrhythmia in the older FAP patients (P = .04). Older patients with LP had increased ventricular septum thickness (P = .02) and left posterior wall thickness (P = .01), as compared with those without LP. In conclusion, ventricular LPs are common in the FAP patients older than 60 years and associated with nonsustained ventricular arrhythmia and increased thickness of the left ventricular wall. Long-term follow-up studies are required to find the prognostic significance of these new findings.

Adult↗

PubMed2005

Serial assessment of variability in heart rate in children with the Fontan circulation.

Autonomic nervous control of the heart can be studied by analysing variability in heart rate. Although earlier studies have shown reduced variability in patients with the Fontan circulation, we are not aware of any previous study examining longitudinal changes in such children. We have examined 13 patients who had undergone total cavopulmonary connection, and 37 healthy controls matched for age and gender. The examinations included complete echocardiography, and 24-hour ambulatory electrocardiogram for analysis of the parameters for variability in heart rate. After the Fontan procedure, three follow-up examinations were performed at a mean of 4.4 years, 5.6 and 7.2 years. Reduced variability was found in those with the Fontan circulation. A significant difference was found between patients and their controls with respect to high-frequency power at the second, p equal to 0.05, and third, p equal to 0.03, examination. The ratio of low-to-high-frequency components progressively increased in those with the Fontan circulation, a phenomenon that led to a significant difference, p equal to 0.03, at the third examination. Our study shows that, in patients with the Fontan circulation, routine ambulatory electrocardiographic monitoring including analysis of variability in heart rate, detects over time a progressive sympatovagal imbalance.

Adolescent↗

PubMed2004

Liver transplantation does not prevent the development of life-threatening arrhythmia in familial amyloidotic polyneuropathy, Portuguese-type (ATTR Val30Met) patients.

BACKGROUND: Orthotopic liver transplantation (OLT) is today the only available treatment to halt the progress of familial amyloidotic polyneuropathy (FAP). Because heart arrhythmia and conduction disturbances are well-known manifestations of FAP, the aim of this study was to investigate the occurrence and development of heart conduction and rhythm disturbances in Swedish FAP patients who underwent liver transplantation. METHODS: Ambulatory 24-hour electrocardiography (ECG) recordings (Holter-ECGs) were available from 30 patients, who had been investigated before and reexamined after OLT. RESULTS.: The number of patients with abnormalities on their ECG recordings increased after OLT. Four patients developed serious arrhythmia after transplantation that necessitated the insertion of a pacemaker 40 months or longer after OLT. CONCLUSIONS: The development of cardiac conduction disturbances and arrhythmias appear not to be halted by liver transplantation, indicating that the physician should be aware of the potential risk for FAP patients receiving transplants to develop fatal arrhythmia. The follow-up after liver transplantation should include Holter-ECG recordings.

Adult↗

PubMed2004

Electromagnetic field exposure and health among RF plastic sealer operators.

Operators of RF plastic sealers (RF operators) are an occupational category highly exposed to radiofrequency electromagnetic fields. The aim of the present study was to make an appropriate exposure assessment of RF welding and examine the health status of the operators. In total, 35 RF operators and 37 controls were included. The leakage fields (electric and magnetic field strength) were measured, as well as induced and contact current. Information about welding time and productivity was used to calculate time integrated exposure. A neurophysiological examination and 24 h ECG were also carried out. The participants also had to answer a questionnaire about subjective symptoms. The measurements showed that RF operators were exposed to rather intense electric and magnetic fields. The mean values of the calculated 6 min, spatially averaged E and H field strengths, in line with ICNIRP reference levels, are 107 V/m and 0.24 A/m, respectively. The maximum measured field strengths were 2 kV/m and 1.5 A/m, respectively. The induced current in ankles and wrists varied, depending on the work situation, with a mean value of 101 mA and a maximum measured value of 1 A. In total, 11 out of 46 measured RF plastic sealers exceeded the ICNIRP reference levels. RF operators, especially the ready made clothing workers had a slightly disturbed two-point discrimination ability compared to a control group. A nonsignificant difference between RF operators and controls was found in the prevalence of subjective symptoms, but the time integrated exposure parameters seem to be of importance to the prevalence of some subjective symptoms: fatigue, headaches, and warmth sensations in the hands. Further, RF operators had a significantly lower heart rate (24 h registration) and more episodes of bradycardia compared to controls.

Adult↗

PubMed2003

Holter ECG monitoring in patients with perceived electrical hypersensitivity.

Earlier studies have indicated that patients claiming to be sensitive to electromagnetic fields, so-called electrical hypersensitivity (EHS), have a dysbalance of the autonomic nervous system (ANS) regulation. This paper focuses on a possible dysbalance in the ANS among EHS patients by the use of long-term monitoring of electrocardiogram (ECG) in both a patient and a matched control group. At the same time, the environmental power frequency magnetic field was recorded for both groups in order to see if there was any difference in exposure between the groups. ECG, heart rate (HR) and heart rate variability (HRV) as well as the magnetic field exposure were monitored for 24 h. Fourteen patients with perceived EHS symptoms were selected from the University Hospital, Umeå, Sweden. Symptoms indicating autonomic nervous dysregulation were not part of the inclusion criteria of the patient group. Age and sex matched healthy subjects were used as controls. No differences were found between the groups regarding magnetic field exposure or the mean HR for 24 h. The HRV analyses showed that the high-frequency (HF) component did not have the expected increase with sleep onset and during nighttime in the EHS group. When separating the sleeping and awake time even less differences between the two conditions in the EHS patients, both for the low-frequency and HF components in the HRV spectrum, were seen. EHS patients had a disturbed pattern of circadian rhythms of HRV and showed a relatively 'flat' representation of hourly-recorded spectral power of the HF component of HRV.

Adult↗