By convention, coronary dominance is dictated by whichever artery supplies the posterior descending artery (PDA) and the posterior left ventricular (PLV) branch.
| Pattern | PDA / PLV supply | Frequency |
|---|---|---|
| Right dominant | The RCA gives rise to the PDA and PLV | ~ 85–89% |
| Left dominant | The LCx gives rise to the PDA and PLV | ~ 8–15% |
| Codominant | Shared between the RCA and LCx | ~ 3–7% |
Knowing the dominance changes how you map wall-motion abnormalities back to a culprit vessel. In a left-dominant patient, an inferior-wall infarct is an LCx event, not an RCA event.