ASSOCIATION BETWEEN PREINFARCTION ANGINA AND A LOWER RISK OF RIGHT-VENTRICULAR INFARCTION

Background Right ventricular infarction occurs in conjunction with inf erior myocardial infarction caused by proximal occlusion of the right coronary artery. However, right ventricular infarction occurs infreque ntly, and the reasons for this are uncertain. Methods We retrospective ly assessed the association between preinfarction angina and right ven tricular infarction, as well as the short-term outcome, in 113 patient s with a first acute inferior myocardial infarction caused by right-co ronary-artery occlusion. The association between the timing of angina during the week before infarction and the clinical outcome was also as sessed. Results The absence of preinfarction angina predicted the deve lopment of right ventricular infarction (odds ratio, 6.3; 95 percent c onfidence interval, 2.7 to 15.1; P<0.001), complete atrioventricular b lock (odds ratio, 3.6; 95 percent confidence interval, 1.4 to 10.3; P= 0.01), and combined hypotension and shock (odds ratio, 12.4; 95 percen t confidence interval, 4.5 to 40.6; P<0.001). Angina 24 to 72 hours be fore infarction was most strongly associated with reductions in the ra tes of right ventricular infarction (adjusted odds ratio, 0.2; 95 perc ent confidence interval, 0 to 0.8; P=0.02) and combined hypotension an d shock (adjusted odds ratio, 0.1; 95 percent confidence interval, 0 t o 0.5; P=0.02). Conclusions Preinfarction angina was an independent pr edictor of the absence of right ventricular infarction in patients wit h acute inferior myocardial infarction. The patients with preinfarctio n angina also had better short-term outcomes than those without preinf arction angina. (C) 1998, Massachusetts Medical Society.