[Geomagnetic pulsations and myocardial infarctions].

Aim: To clarify the role of geomagnetic micropulsations Pc1 (0.2-5s) in the range of the basic heart rate in an increase in the number of myocardial infarctions (MI) and sudden death (SD).

Material And Methods: MI incidence rate in Moscow for 1979-1981, SD incidence rate in Bolgaria for 15 years for rural and urban population and data on micropulsations Pc1 were analysed.

Results: The number of MI rose both in Moscow and Bulgaria when the above micropulsations occurred during geomagnetic disturbances. Season variations of MI and SD incidence are related with a season trend in Pc1 duration with maximum in winter when even moderate magnetic disturbances are biotropic, while in summer even intensive magnetic disturbances do not cause extra number of MI.

Conclusion: Factor intensifying influence of geomagnetic disturbances with Pc1 in winter may be low production of melatonin caused by light insufficiency.