Coronary Artery Dominance and the Pathology of Ischaemic Heart Disease: Dominance-Related Differences in Infarct Size and Collateral Circulation in a Cadaveric Series

Abstract

Background: Left coronary dominance has been linked to adverse outcomes in ischaemic heart disease, but direct anatomical evidence relating dominance to infarct size and collateral development is scarce. We examined these relationships in a cadaveric series.

Methods: Ninety-five formalin-fixed adult human hearts were dissected and classified by dominance. Atherosclerosis was graded, myocardial infarction was characterised by location, size (percentage of left ventricle), and histological age, and the collateral circulation was assessed. Infarct size was compared across dominance groups by ANOVA and categorical variables by the chi-square test.

Results: Coronary atherosclerosis was present in 75 hearts (78.9%) and myocardial infarction in 43 (45.3%). Infarcts were larger in left-dominant hearts than in right-dominant hearts (32.2 ± 8.3% vs 18.4 ± 5.4% of the left ventricle; ANOVA p<0.001), consistent with the greater myocardial territory subtended by the dominant circumflex. Collateral circulation was present in 47.8% of right-dominant, 66.7% of balanced, and 87.5% of left-dominant hearts, a gradient that approached but did not reach significance (p=0.054), likely reflecting the small left-dominant subgroup. Healed infarcts predominated (n=26).

Conclusions: Coronary dominance is associated with infarct size, left-dominant hearts sustaining larger infarcts, with a parallel trend toward greater collateral development. These direct anatomical findings support the adverse prognostic significance attributed to left dominance and the systematic consideration of dominance in ischaemic heart disease.