Effects of Chelation Therapy on QT Dispersion in Lead Exposed Industry Workers in Turkey

Abstract

Background: Occupational lead poisoning is a common and serious occupational health problem, with workers mainly exposed to lead through inhalation and ingestion. A wide range of studies conducted on lead intoxication and its ECG effects, revealed that QT interval is one of the most important parameters. QT dispersion is a marker of heterogeneity and is frequently encountered in patients with a disparity in ventricular recovery and is implicated as a direct marker of cardiovascular mortality. Methods: Battery, metal mine and car service workers who had been working in the same workplace for at least two years and admitted to Ankara Occupational Diseases Hospital for annual examination and hospitalized with toxic blood lead levels, were enrolled in the study. Patients were given chelation therapy with Ca-EDTA, and ECGs were taken before hospitalization and one week after the chelation therapy. Results: A total of 155 male Caucasian workers (mean age = 32 ± 12 years) were evaluated. The mean blood lead level was 55.3 ± 5.1 μg/dL (min = 45.3 μg/dL max = 70.9 μg/dL). None of the participants had an arrhythmic event or death. QT dispersion before chelation and post-therapy was 38.86±13.24 msec and 35.80±12.32 msec, respectively (p=0.000001). Conclusion: Chelation therapy by Ca-EDTA in lead poisoning could reduce ventricular arrhythmias by homogenizing ventricular repolarization times.