Microwave radiation and heart-beat rate of rabbits.

Abstract

Each of three adult New Zealand rabbits, 2 male and 1 female albinos, was exposed dorsally or ventrally, to 2450-MHz plane waves for 20 min under each of several field conditions: 1) to continuous waves (CW) at 5 mW/cm2; 2) to pulsed waves (PW) of 1-microsecond width that recurred 700 pps at an average of 5 mW/cm2 and at a peak of 7.1 W/cm2; 3) to PW of 10-microseconds width at a peak of 13.7 W/cm2 that were synchronized with and triggered by the R wave of the electrocardiogram (EKG) at various delay times (0, 100, and 200 ms; and 4) to CW at 80 mW/cm2. Carbon-loaded Teflon electrodes were used to record the EKG from forelimbs of an animal before, during, and after irradiation whilst it was maintained in a constant exposure geometry in a wooden squeeze box. Field induced changes in the heart-beat rate were observed at 80 mW/cm2 but not a lower average power densities, although a peak positive chronotropic effect might have been occasioned by PM introduced at 100 and 200 ms after the R wave peak. No cumulative effect was observed over a period of four months. Thermographic analysis revealed relatively little absorption of microwave energy by the myocardium irrespective of anatomical aspect of exposure.

AI evidence extraction

Main findings

Field-induced changes in heart-beat rate were observed at 80 mW/cm2 continuous-wave exposure but not at lower average power densities (5 mW/cm2). The authors note a possible peak positive chronotropic effect with pulsed microwaves triggered 100 and 200 ms after the R wave. No cumulative effect was observed over four months, and thermography suggested relatively little myocardial absorption regardless of exposure aspect.

Outcomes measured

• heart-beat rate
• electrocardiogram (EKG)
• myocardial microwave energy absorption (thermographic analysis)

Limitations

• Very small sample size (n=3)
• Animal study; generalizability to humans unclear
• Some findings described as possible (uncertain) rather than definitive

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": "20 min"
    },
    "population": "Adult New Zealand rabbits (2 male, 1 female albinos)",
    "sample_size": 3,
    "outcomes": [
        "heart-beat rate",
        "electrocardiogram (EKG)",
        "myocardial microwave energy absorption (thermographic analysis)"
    ],
    "main_findings": "Field-induced changes in heart-beat rate were observed at 80 mW/cm2 continuous-wave exposure but not at lower average power densities (5 mW/cm2). The authors note a possible peak positive chronotropic effect with pulsed microwaves triggered 100 and 200 ms after the R wave. No cumulative effect was observed over four months, and thermography suggested relatively little myocardial absorption regardless of exposure aspect.",
    "effect_direction": "mixed",
    "limitations": [
        "Very small sample size (n=3)",
        "Animal study; generalizability to humans unclear",
        "Some findings described as possible (uncertain) rather than definitive"
    ],
    "evidence_strength": "very_low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "rabbit",
        "microwave radiation",
        "2450 MHz",
        "continuous wave",
        "pulsed wave",
        "power density",
        "heart rate",
        "chronotropic effect",
        "electrocardiogram",
        "thermography"
    ],
    "suggested_hubs": []
}

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