title: The analysis of QT interval and repolarization morphology of the heart in chronic exposure to lead.
abstract: There are no common recommendations regarding electrocardiographic monitoring in occupationally exposed workers. Therefore, the present study was designed to investigate whether exposure to lead results in an increase of selected electrocardiography (ECG) pathologies, such as QT interval prolongation and repolarization disorders, in occupationally exposed workers. The study group included 180 workers occupationally exposed to lead compounds. The exposed group was divided according to the median of the mean blood lead level (PbBmean) calculated based on a series of measurements performed during 5-year observation period (35 µg/dl) into two subgroups: low exposure (LE, PbBmean= 20.0-35.0 µg/dl) and high exposure (HE, PbBmean= 35.1-46.4 µg/dl). The control group consisted of 69 healthy workers without occupational exposure to lead. ECG evaluation included the analysis of heart rate (HR), QT interval and repolarization abnormalities. Mean QT interval was significantly greater in the exposed population than in the control group by 2%. In the HE group, mean QT interval was significantly greater than in the control group by 4% and significantly different from those noted in the LE group. Positive correlations between QT interval and lead exposure indices were also reported. Besides, there was a negative correlation between HR and blood lead level. Increased concentration of lead in the blood above 35 μg/dl is associated with the QT interval prolongation, which may trigger arrhythmias when combined with other abnormalities, such as long QT syndrome. Therefore, electrocardiographic evaluation should be a part of a routine monitoring of occupationally exposed populations.
authors.affiliation: 1 Department of Internal Medicine, Independent Public Health Care Centre in Staszów, Staszów, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Kiełtucki
authors.affiliation: 2 Department of Biochemistry, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Katowice, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Dobrakowski
authors.affiliation: 3 Department of Pharmacology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Katowice, Poland.
authors.forename: N
authors.initials: N
authors.lastname: Pawlas
authors.affiliation: 4 Department of Cardiology, Congenital Heart Diseases, and Electrotherapy, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Katowice, Poland.|5 Silesian Center for Heart Diseases, Zabrze, Poland.
authors.forename: B
authors.initials: B
authors.lastname: Średniawa
authors.affiliation: 6 Institute of Occupational Medicine and Environmental Health in Sosnowiec, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Boroń
authors.affiliation: 2 Department of Biochemistry, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Katowice, Poland.
authors.forename: S
authors.initials: S
authors.lastname: Kasperczyk
mesh_terms: D000328:Adult; D000395:Air Pollutants, Occupational / Q000097:blood / Q000633:toxicity*; D004562:Electrocardiography; D004784:Environmental Monitoring; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007854:Lead / Q000097:blood / Q000633:toxicity*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D011524:Protoporphyrins / Q000097:blood
chemical_list: D000395:Air Pollutants, Occupational; D011524:Protoporphyrins; C017803:zinc protoporphyrin; D007854:Lead
keywords: ECG; Lead poisoning; QT interval; repolarization