QTc interval and electrocardiographic changes by type of shift work

Authors

  • Michele Meloni MD,

    Corresponding author
    • Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Monserrato (Cagliari), Italy
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  • Davide Setzu MD,

    1. Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Monserrato (Cagliari), Italy
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  • Alberto Del Rio MD,

    1. Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Monserrato (Cagliari), Italy
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  • Marcello Campagna MD,

    1. Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Monserrato (Cagliari), Italy
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  • Pierluigi Cocco MD

    1. Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Monserrato (Cagliari), Italy
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  • Disclosure Statement: The authors report no conflicts of interests.

Correspondence to: Michele Meloni, MD, Dipartimento di Sanità Pubblica, Medicina Clinica e Molecolare Sezione di Medicina del Lavoro, Università di Cagliari, Asse didattico E, S.S. 554, Km 4,500, 09042 Monserrato (Cagliari), Italy. E-mail: melonim@medicina.unica.it

Abstract

Background

We conducted a cross sectional survey of electrocardiographic changes among shift-workers.

Methods

We classified the electrocardiogram morphology, and measured the QTc interval in 91 male workers engaged in regular daily work-shifts, 32 in 24 hr work-shift (h24), and 93 in irregular 6 hr work-shift (h6).

Results

With reference to daily workers, the QTc interval was prolonged among h6 workers (P < 0.001) and h24 workers (P < 0.005). The age- and obesity-adjusted standardized prevalence ratio (SPR) of a borderline/prolonged QTc was 2.2-fold among h6 workers (95% CI 1.2, 4.2); conduction disorders (SPR = 2.6; 95% CI 1.3, 5.2) and repolarization disorders (SPR = 1.9; 95% CI 1.0, 3.5) were also more frequently observed among h6 workers. Excluding 19 subjects with risk factors for prolonged QTc did not change the results.

Conclusions

Our study reveals significant changes in the ECG morphology in relation to shift-work, especially in unpredictable and non-standard working hours. Am. J. Ind. Med. 56:1174–1179, 2013. © 2013 Wiley Periodicals, Inc.

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