Influence of acute microwave radiation on cardiac function in normal and myocardial ischemic cats.

Abstract

Exposure of biological specimens to microwave radiation in vivo and in vitro has been reported to cause alterations to the cardiovascular system. In addition, microwave radiation may cause effects in damaged cardiac tissue that are not observed in normal tissue. In this study, we examined the influence of direct microwave irradiation (2.45 GHz, continuous wave) of the intact exposed heart on cardiac function in cats with and without myocardial ischemia. Myocardial ischemia was induced by occlusion of the left anterior descending coronary artery. In the sham-nonexposed and sham-plus-microwave exposed animals the coronary artery was isolated but not occluded. The exposed hearts were either irradiated at a specific absorption rate (SAR) of 30 mW/g or not irradiated, and were monitored for 5 h. At a SAR of 30 mW/g, the temperature of the exposed tissue increased at an initial rate of 0.43 degrees C/min in dead cats. However, in live animals, no increases in aortic blood temperatures occurred during irradiation. Mean arterial blood pressure, cardiac output, heart rate, plasma and myocardial creatine phosphokinase, and S-T segment were not influenced by 5 h of microwave irradiation of the myocardium in cats with or without myocardial ischemia.

AI evidence extraction

Main findings

Direct continuous-wave 2.45 GHz irradiation of the exposed myocardium for 5 h at SAR 30 mW/g did not influence mean arterial blood pressure, cardiac output, heart rate, plasma or myocardial creatine phosphokinase, or S-T segment in cats with or without myocardial ischemia. In dead cats, exposed tissue temperature increased initially (0.43°C/min), while in live animals no increases in aortic blood temperature occurred during irradiation.

Outcomes measured

• Mean arterial blood pressure
• Cardiac output
• Heart rate
• Plasma creatine phosphokinase
• Myocardial creatine phosphokinase
• S-T segment
• Aortic blood temperature
• Exposed tissue temperature (dead cats)

Limitations

• Sample size not reported in abstract
• Only one frequency (2.45 GHz) and one SAR level (30 mW/g) described
• Acute exposure duration (5 h) only
• Direct irradiation of an intact exposed heart may not generalize to typical environmental/consumer exposures

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": "direct microwave irradiation of exposed heart",
        "frequency_mhz": 2450,
        "sar_wkg": 30,
        "duration": "5 h"
    },
    "population": "Cats with and without experimentally induced myocardial ischemia (left anterior descending coronary artery occlusion)",
    "sample_size": null,
    "outcomes": [
        "Mean arterial blood pressure",
        "Cardiac output",
        "Heart rate",
        "Plasma creatine phosphokinase",
        "Myocardial creatine phosphokinase",
        "S-T segment",
        "Aortic blood temperature",
        "Exposed tissue temperature (dead cats)"
    ],
    "main_findings": "Direct continuous-wave 2.45 GHz irradiation of the exposed myocardium for 5 h at SAR 30 mW/g did not influence mean arterial blood pressure, cardiac output, heart rate, plasma or myocardial creatine phosphokinase, or S-T segment in cats with or without myocardial ischemia. In dead cats, exposed tissue temperature increased initially (0.43°C/min), while in live animals no increases in aortic blood temperature occurred during irradiation.",
    "effect_direction": "no_effect",
    "limitations": [
        "Sample size not reported in abstract",
        "Only one frequency (2.45 GHz) and one SAR level (30 mW/g) described",
        "Acute exposure duration (5 h) only",
        "Direct irradiation of an intact exposed heart may not generalize to typical environmental/consumer exposures"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "2.45 GHz",
        "continuous wave",
        "specific absorption rate",
        "SAR",
        "cat",
        "myocardial ischemia",
        "cardiac function",
        "coronary artery occlusion",
        "creatine phosphokinase",
        "ST segment",
        "temperature"
    ],
    "suggested_hubs": []
}

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