Cardiovascular disorders

I./1.4.: Coronary dominance

First and foremost, it is essential to stress that the LCA almost always supplies the largest portion (approximately 60-65 %) of the ventricular myocardium, thus the LCA can be considered as dominant vessel. The terms of left or right coronary dominance bear a relation to the distribution pattern of coronary branches only on the diaphragmatic (inferior) aspect of the heart. In terms of dominance, hearts in which the RCA gives rise to the posterior descending artery nourishing the inferior (posterior) aspect of the interventricular septum and to branches to the posterior wall of the left ventricle are classified as “right dominant”. Approximately 85 % of the population is right dominant. Conversely, if these arteries originate from the LCA, the type of coronary distribution can be classified as “left dominant”. About 8% of cases are left dominant. In “co-dominant” or “balanced” type of coronary distribution, the left circumflex artery reaches the crux and supplies solely the diaphragmatic aspect of the left ventricle, while the posterior portion of the interventricular septum is nourished by the posterior descending artery from the RCA (approximately 7%).