There is a delay of several days between thrombi or plaque rupture and onset of acute myocardial infarction (AMI), a Japanese study published in 24 October Circulation suggests. In the study, investigators from Gifu University School of Medicine studied 20 patients who had coronary angiograms performed within one week before AMI and 20 controls who had coronary angiograms performed between six and 18 months before AMI. The two groups did not differ significantly in any relevant baseline parameters. Angiographic analysis revealed that infarct-related coronary segments (IRCS) three days before AMI tended to have a significant stenosis of >50% and Ambrose's type II eccentric lesions — an indicator of plaque rupture and/or thrombi. Typical features at one year before AMI were mild stenosis of <50% with rare Ambrose's type II eccentric lesions, plus multiple irregularities. Analysis of subgroups according to the type of infarction — Q-wave infarction, non-Q-wave infarction, preceding effort...