The analysis of QT interval and repolarization morphology of the heart in chronic exposure to lead

Abstract

<jats:p> 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 (PbB<jats:sub>mean</jats:sub>) calculated based on a series of measurements performed during 5-year observation period (35 µg/dl) into two subgroups: low exposure (LE, PbB<jats:sub>mean</jats:sub> = 20.0–35.0 µg/dl) and high exposure (HE, PbB<jats:sub>mean</jats:sub> = 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. </jats:p>

Response to Letter: Novel Electrocardiographic Indices of Arrhythmogenesis and Blood Lead Level

“…At this point, it will be more accurate to make comments compared to the control group. In other electrocardiographic studies in the literature, although parameters such as PR interval, QRS duration, and QTc in the lead-exposed and control groups were within normal limits, they were significantly higher in the exposure group than in the control group (Chen et al, 2013;Kieltucki et al, 2016).…”

Functional consequences of lead and mercury exposomes in the heart

“…Changes in heart excitability have been associated with the levels of the Pb 2+ exposome. Correlations have also been established between Pb 2+ exposomes and heart automatism, and conduction observed in electrocardiograms (ECG) of populations living or working in certain regions with increased risk of Pb 2+ exposure (Jing et al, 2019;Kiełtucki et al, 2017). These latter studies report a Pb 2+ -mediated prolongation in the QT interval (Chen et al, 2013Kiełtucki et al, 2017 and alterations in the QRS-T angle (Jing et al, 2019).…”

Key Characteristics of Cardiovascular Toxicants

“…There is evidence that lead exhibits KCs 1, 2, 5, 7, 8, 10, 11, and 12. Occupational exposure modulated cardiac conduction (KC1) ( Kiełtucki et al. 2017 ) and acute exposure altered cardiac excitability in isolated guinea pig hearts ( Ferreira de Mattos et al.…”