EMF-Portal | Thermal bradycardia during radiofrequency irradiation

Thermal bradycardia during radiofrequency irradiation med./bio.

By: Jauchem JR, Frei MR, Heinmets F

Published in: Physiol Chem Phys Med NMR 1983; 15 (5): 429-434

Aim of study (acc. to author)

Endpoint

Exposure

Exposure	Parameters
Exposure 1: 2.8 GHz Modulation type: pulsed Exposure duration: intermittent, about 7-10 min on/9-14 min off, for 2 x 3 cycles, see below	power density: 60 mW/cm² mean SAR: 14 W/kg mean ([Durney et al., 1978])

Frequency	2.8 GHz
Type	electromagnetic field
Exposure duration	intermittent, about 7-10 min on/9-14 min off, for 2 x 3 cycles, see below

Exposure source	horn antenna anechoic chamber S-band magnetron source
Setup	Anaesthetized animals were exposed in the H-orientation with their long axis parallel to the H-field.
Additional info	Animals were exposed until their colonic temperature rose to 39.5°C. Exposure was repeated when the temperature returned to 38.5°C. This procedure was repeated for three cycles. Then, at 38.5°C, either atropine sulphate or saline was administered i.p. After a 15 min interval, exposure was resumed for another three (or four?) cycles [Heinmets, 1982].

Measurand	Value	Type	Method	Mass	Remarks
power density	60 mW/cm²	mean	measured	-	-
SAR	14 W/kg	mean	estimated	-	[Durney et al., 1978]

The power density was determined with an EMR monitor and a probe. The generator power was monitored with a power meter.

Durney CH et al. (1986): Radiofrequency Radiation Dosimetry Handbook (4th Edition)
Heinmets F (1982): Pilot experiments on temperature cycling in rats exposed repetitively to radiofrequency radiation (RFR)

Methods Endpoint/measurement parameters/methodology

Investigated system:

Investigated organ system:

Time of investigation:

Main outcome of study (acc. to author)

During an initial irradiation period to raise colonic temperature to 39.5°C, heart rate decreased significantly. Intermittent exposure to irradiation, which resulted in 1°C colonic temperature changes, did not significantly affect heart rate or mean arterial blood pressure, before or after atropine administration. The time courses of these 1°C temperature changes were not changed significantly by atropine. Following administration of atropine, the thermal bradycardia during the initial heating period was still evident. It is possible that the bradycardia is a consequence of a general reduction in metabolism, which is observed also during environmental heat exposure.

Study character:

Study funded by

Air Force, USA