Disruption of Circadian Rhythms by Shift Work Exacerbates Reperfusion Injury in Myocardial Infarction

Background: Shift work is associated with increased risk of acute myocardial infarction (AMI) and worsened prognosis. However, the mechanisms linking shift work and worsened prognosis in AMI remain unclear.

Objectives: This study sought to investigate the impact of shift work on reperfusion injury, a major determinant of clinical outcomes in AMI.

Methods: Study patient data were obtained from the database of the EARLY-MYO-CMR (Early Assessment of Myocardial Tissue Characteristics by CMR in STEMI) registry, which was a prospective, multicenter registry of patients with ST-segment elevation myocardial infarction (STEMI) undergoing cardiac magnetic resonance (CMR) imaging after reperfusion therapy. The primary endpoint was CMR-defined post-reperfusion infarct size. A secondary clinical endpoint was the composite of major adverse cardiac events (MACE) during follow-up. Potential mechanisms were explored with the use of preclinical animal AMI models.

Results: Of 706 patients enrolled in the EARLY-MYO-CMR registry, 412 patients with STEMI were ultimately included. Shift work was associated with increased CMR-defined infarct size (β = 5.94%; 95% CI: 2.94-8.94; P < 0.0001). During a median follow-up of 5.0 years, shift work was associated with increased risks of MACE (adjusted HR: 1.92; 95% CI: 1.12-3.29; P = 0.017). Consistent with clinical findings, shift work simulation in mice and sheep significantly augmented reperfusion injury in AMI. Mechanism studies identified a novel nuclear receptor subfamily 1 group D member 1/cardiotrophin-like cytokine factor 1 axis in the heart that played a crucial role in mediating the detrimental effects of shift work on myocardial injury.

Conclusions: The current study provided novel findings that shift work increases myocardial infarction reperfusion injury. It identified a novel nuclear receptor subfamily 1 group D member 1/cardiotrophin-like cytokine factor 1 axis in the heart that might play a crucial role in mediating this process. (Early Assessment of Myocardial Tissue Characteristics by CMR in STEMI [EARLY-MYO-CMR] registry; NCT03768453).