title: [Geomagnetic pulsations and myocardial infarctions].
abstract: OBJECTIVE
  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).
  
  
  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.
  
  
  CONCLUSIONS
  Factor intensifying influence of geomagnetic disturbances with Pc1 in winter may be low production of melatonin caused by light insufficiency.
authors.forename: S I
authors.initials: SI
authors.lastname: Rapoport
authors.forename: T K
authors.initials: TK
authors.lastname: Breus
authors.forename: O V
authors.initials: OV
authors.lastname: Kozyreva
authors.forename: N K
authors.initials: NK
authors.lastname: Malinovskaia
mesh_terms: D002031:Bulgaria / Q000453:epidemiology; D004632:Emergency Medical Services / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008280:Magnetics; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012424:Rural Population; D012426:Russia / Q000453:epidemiology; D012621:Seasons; D015996:Survival Rate / Q000639:trends; D014505:Urban Population