Objective: We set out to study the effect of the location of the culprit coronary lesion on myocardial infarction (MI) fatality by combining data from MI survivors in the coronary care unit (CCU) and autopsied patients with pre-hospital fatal MI.
Design: We studied two simultaneous series of men under 70 years with fatal pre-hospital MI (n = 36) and men admitted for acute ST-elevation-MI (n = 92). The culprit lesion was identified by the presence of thrombus at autopsy and by coronary angiography in patients admitted to the CCU.
Results: The culprit lesion was located in the right coronary artery (RCA) in 22 (61%) of 36 men with fatal MI compared to 30 (33%) of 92 men with non-fatal MI (P = 0.01). Seventy-three percent of fatal RCA occlusions were proximal as opposed to only 30% of non-fatal RCA occlusions (P < 0.001). Forty-four percent of all fatal MI were due to proximal RCA occlusion as opposed to only 10% of non-fatal MI (P < 0.005).
Conclusions: Proximal RCA occlusions were very often found among men with fatal pre-hospital MI, whereas left-sided coronary occlusions were significantly more frequent in hospital-admitted survivors of MI. Left-sided coronary occlusions may be associated with a more favourable pre-hospital phase of acute MI compared to proximal RCA occlusions.