Background: The significance of heavy metals in pathogenesis of the circulatory system diseases remains unresolved. The aim of the study was to evaluate electrocardiographic changes in workers occupationally exposed to lead without clinical presentation of cardiac involvement.
Methods: A group of 60 smelters and refiners and 45 healthy men, as a control group, were enrolled. Twelve-lead electrocardiogram (ECG) and 24-hour Holter monitoring were performed. Further analysis included heart rate variability (HRV) in time and frequency domains and heart rate turbulence (HRT).
Results: Analysis of 12-lead ECG recordings revealed various pathologies in 27 out of 60 men occupationally exposed to lead. Twenty-four-hour ECG Holter monitoring showed the higher mean heart rate in copper smelters than in healthy subjects (85.8 ± 14.1 bpm vs 72.6 ± 9.2 bpm; P < 0.05) and more premature supraventricular and ventricular contractions (298 ± 235 vs 27 ± 45; P < 0.05 and 152 ± 138 vs 18 ± 18; P < 0.05, respectively). The majority of time domain and frequency domain HRV parameters were significantly lower, and the LF:HF ratio was higher when compared with the control group. Turbulence onset was abnormal in six copper smelters and turbulence slope in five men exposed to lead.
Conclusions: Electrocardiographic evaluation showed that various heart rhythm disorders were more frequent in metallurgists, as compared to the control group, and the decreased HRV and abnormal parameters of HRT were observed. Noninvasive electrocardiographic evaluation could be a valuable method of the early prediction of cardiovascular disorders in men occupationally exposed to lead.
©2011, Wiley Periodicals, Inc.