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 ¼ 2.6; 95% CI 1.3, 5.2) and repolarization disorders (SPR ¼ 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.
QTc interval and electrocardiographic changes by type of shift work
DEL RIO, ALBERTO;CAMPAGNA, MARCELLO;COCCO, PIER LUIGI
2013-01-01
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 ¼ 2.6; 95% CI 1.3, 5.2) and repolarization disorders (SPR ¼ 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.
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