The syndrome is the consequence of disruption of a vulnerable coronary
artery plaque, complicated by intraluminal thrombosis, embolization, and
varying degrees of obstruction to perfusion.
The severity of coronary arterial obstruction and the volume of
affected myocardium determine the characteristics of clinical
presentation. Patients with complete occlusion may manifest ST segment
elevation infarction if the lesion occludes an artery supplying a
a substantial volume of the myocardium, but the same occlusion in the presence
of extensive collateralization may manifest as infarction without ST
segment elevation (non-ST elevation ACS).