Increased plaque rupture forms peak incidence of acute myocardial infarction in winter

It has been widely documented that circannual variation has an impact on the incidence and prognosis of cardiovascular diseases. It is unclear why cold ambient temperature increase the incidence of acute myocardial infarction (AMI). We investigated the relationship between the ambient temperature at the onset of AMI, the morphology of the culprit lesion in patients with AMI. We investigated 202 consecutive patients with AMI who underwent optical coherence tomography (OCT). The participants were divided into lower (n = 100) and higher (n = 102) temperature groups based on the ambient temperature. The culprit lesion morphology was compared between the two groups. The median temperature at the onset of AMI was 16.6 °C. The prevalence of plaque ruptures was higher at lower temperatures (lower 66% vs. higher 45%, p = .003), whereas OCT-erosion was more frequent in the higher temperature group (lower 13% vs. higher 26%, p = .021). The lower temperature group showed more cholesterol crystals (lower 71% vs. higher 54%, p = .014). The peak incidence of AMI in the winter is formed by increased plaque rupture, suggesting environmental temperature has an influence on the pathogenesis of AMI. •The onset of AMI demonstrates a bimodal distribution according to the ambient temperature.•AMI is most likely to occur at two specific temperatures: ~10 and ~ 20 °C.•Plaque rupture was more frequent in the colder ambient temperature.•OCT-erosion was more frequent in the higher ambient temperature.