[Electrocardiographic examination of the heart and the study of catecholamine secretion in workers subjected to mechanical vibration and occupational noise].

Electrocardiographic tests in 281 workers of metallurgical industry, exposed for 3-20 years to mechanical and acoustic vibrations exceeding allowable standards, were carried out. The control group consisted of 120 subjects unexposed to physical or chemical hazards. In 82 subjects exposed to vibration and noise, 43 workers exposed to isolated noise and 30 subjects of the control group, the amount of 3 methoxy--4 hydroxymandelic (3M4HM) acid before and after work was determined. Significantly more frequent repolarization disturbances of neurovegetative nature (V-3), particularly in those simultaneously exposed to general and local vibration, were evidenced. In those exposed exclusively to noise no ECG changes were found. In addition, increased 3M4HM secretion, due to both local and whole--body transmitted vibration, was found. Isolated noise does not induce an increase in 3M4HM secretion.