QTc interval and electrocardiographic changes by type of shift work

Area of Science:

• Occupational Health
• Cardiology
• Physiology

Background:

• Shift work is prevalent across various industries.
• Electrocardiographic (ECG) changes associated with shift work are not fully understood.
• Assessing ECG parameters in different shift work schedules is crucial for occupational health.

Purpose of the Study:

• To investigate electrocardiogram (ECG) morphology and QTc interval variations among different shift work schedules.
• To determine the prevalence of conduction and repolarization disorders in relation to shift work patterns.

Main Methods:

• Cross-sectional survey of 91 daily workers, 32 24-hour shift workers (h24), and 93 irregular 6-hour shift workers (h6).
• Classification of ECG morphology and measurement of QTc interval.
• Calculation of standardized prevalence ratios (SPR) adjusted for age and obesity.

Main Results:

• Prolonged QTc intervals were observed in h6 (P < 0.001) and h24 (P < 0.005) workers compared to daily workers.
• Irregular 6-hour shift workers (h6) showed a 2.2-fold increased risk of borderline/prolonged QTc.
• Higher prevalence of conduction (SPR = 2.6) and repolarization disorders (SPR = 1.9) in h6 workers.

Conclusions:

• Shift work, especially irregular schedules, is associated with significant ECG morphology changes.
• Unpredictable work hours may increase cardiovascular risks, indicated by prolonged QTc and conduction/repolarization disorders.
• Further research into mitigating ECG changes in shift workers is warranted.