Changes in frequency of premature complexes and heart rate variability related to shift work
- aDivision of Human Nutrition and Epidemiology, Wageningen University, The Netherlands, bDepartment of Epidemiology, Maastricht University, PO Box 616, 6200 MD, The Netherlands, cLeiden Foundation for ECG analysis SEAL, Leiden University Medical Centre, The Netherlands, dDepartment of Cardiology
- Dr L G P M van AmelsvoortLgpm.vanamelsvoort{at}epid.unimaas.nl
- Accepted 7 June 2001
Abstract
OBJECTIVES To investigate whether an increased risk of cardiovascular disease might be caused by increased arrhythmogeneity and by unfavourable changes in autonomic cardiac control the changes in the occurrence of premature complexes (PVCs) and in heart rate variability (HRV) were studied in subjects who started to work in shifts.
METHODS 1 Year changes in frequency of PVCs and HRV were measured in 49 shift workers and 22 control subjects working in daytime. All respondents were starting in a new job in integrated circuit or waste incinerator plants.
RESULTS The incidence of PVC increased significantly in shift workers over the 1 year follow up, compared with daytime workers. The frequency of ventricular extrasystoles increased in 48.9% of the shift workers, and in 27.3% of the daytime workers. The Spearman correlation coefficient between the number of nights worked and the change in PVCs was 0.33 (p=0.004). A small non-significant unfavourable change in HRV was found in both the shift and daytime workers.
CONCLUSIONS A change in arrhythmogeneity, but not in cardiac autonomic control, might explain the increased risk of cardiovascular disease in shift workers.
