Study type: Medical/biological study (experimental study)

The insensitivity of frog heart rate to pulse modulated microwave energy med./bio.

By: Liu LM, Rosenbaum FJ, Pickard WF
Published in: J Microw Power 1976; 11 (3): 225-232
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Aim of study (acc. to author)

To examine if pulse modulated microwave exposure is capable to induce tachycardia in frog hearts. The experiments were carried out both in situ and in vitro.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.42 GHz
Modulation type: pulsed
Exposure duration: continuous for about 100 s (100 heart beats)
Exposure 2: 10 GHz
Modulation type: pulsed
Exposure duration: continuous for about 100 s (100 heart beats)
Exposure 3: 1.42 GHz
Modulation type: pulsed
Exposure duration: continuous for about 100 s (100 heart beats)

Exposure 1

Main characteristics
Frequency 1.42 GHz
Type
Exposure duration continuous for about 100 s (100 heart beats)
Additional info in vivo
Modulation
Modulation type pulsed
Pulse width 100 µs
Repetition frequency 1 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 0 mm
Setup A semi-rigid 3.58 mm diameter coaxial microprobe delivering the MW energy was lightly pressed against the sinus venosus, i.e. the pacemaker of the frog's heart.
Additional info Two small alligator clips were used for ECG electrodes, one connected on the right side of the neck and the other one on the left thigh. The MW pulse was triggered by the ECG R-wave and was delivered to the heart on the rising phase of the R-wave near its peak.
Parameters
Measurand Value Type Method Mass Remarks
power 160 mW peak value measured and calculated - -
power 16 µW mean measured and calculated - -
Additional parameter details

The powers indicated above were delivered to the vicinity of the heart and determined from incident and reflected powers. The mean power was calculated at one 100-µs pulse per second.

Exposure 2

Main characteristics
Frequency 10 GHz
Type
Exposure duration continuous for about 100 s (100 heart beats)
Additional info in vivo
Modulation
Modulation type pulsed
Pulse width 100 µs
Repetition frequency 1 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 0 mm
Parameters
Measurand Value Type Method Mass Remarks
power 122 mW peak value measured and calculated - -
power 12 µW mean measured and calculated - -

Exposure 3

Main characteristics
Frequency 1.42 GHz
Type
Exposure duration continuous for about 100 s (100 heart beats)
Additional info in vitro
Modulation
Modulation type pulsed
Pulse width 100 µs
Repetition frequency 1 Hz
Exposure setup
Exposure source
  • coaxial microprobe
Distance between exposed object and exposure source 1 mm
Setup The heart was placed ventral side up in a plastic case filled with aerated frog Ringer's solution where it rested lightly on two parallel stainless steel needles used as ECG electrodes. It was positioned with the sinus venosus against a 1-mm thick Lucite window, and the coaxial microprobe was lightly pressed against the outside of the window.
Additional info The MW pulse was triggered either by the ECG P-wave or by the R-wave.
Parameters
Measurand Value Type Method Mass Remarks
power 70 mW peak value measured and calculated - -
power 7 µW mean measured and calculated - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

For both studies, the in situ heart study and the isolated heart study, no significant changes in heart rate were observed.

Study character:

Study funded by