Influence of smoking on the location of acute myocardial infarctions.

Objective. To determine whether there is an association between smoking and the location of acute myocardial infarctions. Methods. Using a cohort from our hospital and published cohorts from Ireland, Uruguay, and Israel, we calculated odds of having an inferior wall as opposed to an anterior wall acute myocardial infarction among smokers and nonsmokers. Results. In our cohort, there was a higher proportion of smokers than nonsmokers in patients with inferior acute myocardial infarctions than in patients with anterior infarctions. This difference was also present in each of the other cohorts. Odds ratios for an inferior versus an anterior acute myocardial infarction among smokers ranged from 1.15 to 2.00 (median odds ratio, 1.32). When the cohorts were combined (n = 3, 160), the pooled odds ratio for an inferior as opposed to an anterior acute myocardial infarction among smokers was 1.38 (95% confidence interval, 1.20 to 1.58) (P < .002). Conclusions. Cigarette smoking increases the risk of inferior wall acute myocardial infarction more than the risk of anterior wall infarction. Smoking thus appears to adversely affect the right coronary arterial circulation to a greater extent than the left coronary arterial circulation by a mechanism not yet understood.