摘要：To reveal the cardiovascular (CV) system response to occupational exposure to low levels of extremely low frequency (ELF) electric and magnetic fields. Material and methods : Cross-sectional study (first step) for a two years cohort study has been done. Exposure evaluation comprised magnetic flux density and electric fields intensity measurements as well as ergonomic analysis. Health status assessment included detailed occupational anamnesis, clinical and biochemical examinations, computerized ECG and CV function tests. Results and discussion : We have studied 58 subjects occupationally exposed in electric transform and transport facilities (electricians) and 89 electric train drivers. We have used 93 matched care controls. The measured ELF fields had magnetic flux densities of 1.8-34.5 m T for electricians and 0.8-18 m T for train drivers. The intensities of electric fields ranged between 1.5kV/m and 32kV/m for electricians and between 25V/m and 0.5 kV/m for electric train drivers. The measured values did not exceed general accepted permissible levels. Arrhytmias were found at 20.2% of the train drivers vs. 8.1% in controls (OR=3.11, 95% CI: 1.14-8.76) as well as in 20.7% of the electricians (OR=3.2, 95% CI: 1.08-9.77). Conduction disturbances were found in 16.8% of the train drivers vs. 5.4% in controls (OR=3.57, 95% CI: 1.15-13.06) as well as in 36.2% of the electricians vs. 5.4% in controls (OR=9.99, 95% CI: 3.28-35.90). It is to be mentioned the difference between electricians and drivers: OR=2.8, 95% CI: 1.21-6.51. Myocardial ischemia changes were found in 33.7% of the train drivers vs. 8.6% in controls (OR=5.4, 95% CI: 2.18-5.84) as well as at 32.8% of the electricians (OR=5.18, 95% CI: 1.93-14.24). Conclusions : The study of CV effects in ELF fields exposure, revealed significantly frequent ECG changes: arrhytmias , conduction disturbances, and myocardial ischemia changes. The ELF fields’ occupational exposure seems to be a CV risk factor.
关键词：Electric and magnetic fields, cardiovascular system, ECG changes
