Inferior acute myocardial infarction caused by left anterior descending coronary artery, worse prognosis? experience in our center

Type of funding sources: None.

Key diagnostic test in acute myocardial infarction with ST segment elevation(STEMI)is 12-lead electrocardiogram, which guides initial treatment and informs about area at necrosis risk, necrosis extension, and culprit coronary artery. ST elevation in leads II, III, aVF is related to obstruction of right coronary artery(RCA)or circumflex artery. Inferior STEMI with occlusion of left anterior descending artery(LAD)has been described. Our goal is to analyse incidence and characteristics of inferior STEMI due to LAD occlusion.

Observational retrospective study, of patients admitted to our Coronary Care Unit due to inferior STEMI, between08/2011-12/2020. We analysed all patients whose culprit artery was LAD and a random sample of138patients among those with RCA as culprit. Chi-square, Student-t or Mann-Whitney tests were used.

there were a total of2498acute coronay syndromes, 1541were STEMI. 47.7%of them(n:735)were from inferior wall. From inferior STEMI, 12were caused by LAD occlusion(1.6%, 95%confidence interval0.8-2.8%), representing0.8%of all STEMI. There were21.3%women(n:32)and a mean age of61.6 ± 12.5years, without differences by culprit artery. STEMI related with RCA presented a 28.3% of  either right ventricular dysfunction or atrioventricular block, versus none of those related to LAD(p0.037). There was difference in dominance: STEMI caused by LAD presented right dominance in72.7%of cases, while caused by RCA in94.4%(p0.034). All inferior LAD STEMIs had normal left ventricular ejection fraction(LVEF) at admission. There was no statistically significant difference in LVEF at discharge(RCA54.3 ± 7.6vsLAD50.5 ± 13.6), but there was in maximum troponin, which was higher in those STEMI related to RCA(2208 ± 1756mg/dl vs 4095 ± 3833mg/dl, p0.040). Complementary comparisons in Table.

we found that1.6%of inferior STEMI are caused by LAD occlusion instead of RCA or circumflex coronary artery. These STEMI do not cause more severe affectation of left ventricle and run without typical complications of inferior STEMI.