Abstract
Background: Work-related stress is a potential cardiovascular risk factor, but the underlying mechanism is not fully explained. The autonomic nervous system control of cardiac function might play a specific role; therefore, monitoring the QT interval in the electrocardiogram can highlight an autonomic imbalance induced by occupational stressors. The aim of our study was to explore the QT interval parameters as early indicators of imbalance of the autonomic cardiac function in relation to work-related stress. Methods: During 2015–2016 annual workplace health surveillance, we measured work-related stress in 484 workers of a logistic support company using the Health and Safety Executive (HSE) tool. We assessed the frequency-corrected QT (QTc) interval and the QT index (QTi) on the electrocardiogram of each participant, and collected demographic and clinical data. We compared the QTc values by the four Karasek’s categories (active/passive jobs, low/high strain job), and by job support (present/lacking), and conducted multivariate analysis to adjust for possible confounders. Results: The results of the multivariate regression analysis showed that QTc was prolonged among workers operating at a specific site where stress level was found to be elevated. Regular physical activity showed a beneficial effect against QTc prolongation. We did not observe an effect on QTc length by the cross-combined Karasek’s categories of job control, job demand, and job support. Conclusions: Our study suggests subclinical effects of conditions associated with work-related stress on the autonomic regulation of cardiac function. Further research is warranted to elucidate the combined effect of work organization and lifestyle factors on autonomic cardiac function.
Highlights
The activation of the sympathetic nervous system promotes the release of catecholamines through the hypothalamic–pituitary–adrenal axis, which prolongs the effect on heart rate and heart rate variability (HRV) elicited though the neural route response [7]
Whether the QT interval parameters calculated on the electrocardiogram tracing (ECG) predict risk of sudden death is controversial [9,10]; still, their use has been proposed along with heart rate variability (HRV) as biomarkers of stress-related changes in the early detection of autonomic imbalance [11,12,13]
Since flight logistic workers are potentially exposed to work-related stress and to organizational factors with a putative role on the onset of stress and related adverse health outcomes, there is a need for studies that consider these aspects in a unique framework
Summary
Whether the QT interval parameters calculated on the electrocardiogram tracing (ECG) predict risk of sudden death is controversial [9,10]; still, their use has been proposed along with heart rate variability (HRV) as biomarkers of stress-related changes in the early detection of autonomic imbalance [11,12,13]. While HRV has not always been recognized as a CVD predictor [14,15], the heart rate-corrected QT parameters (QTc = QT corrected, and QTi = QT index) have been used as biomarkers of autonomic dysfunction following work-related stress. Measurement of the ECG QTc interval was originally proposed to predict the polymorphic ventricular tachycardia, known as Torsades de pointes, consisting of oscillations of the QRS complex around the isoelectric line This syndrome is associated with the occurrence of syncope episodes, with possible evolution to ventricular fibrillation and sudden death [18]. Results: The results of the multivariate regression analysis showed that QTc was prolonged among workers operating at a specific site where stress level was found to be elevated
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