Posterior descending (posterior interventricular) artery
Branch · Right dom. 70-85% Left dom. 5-10% Co-dom. ~10%
Runs in the posterior interventricular groove toward the apex. Whichever artery gives it defines dominance: the RCA in about 70 to 85% (right dominant), the circumflex in 5 to 10% (left dominant), and both in the remainder (co-dominant).
Traced from the start
- Right (anterior) aortic sinus
- Left (posterior) aortic sinus and left main stem
- Right coronary arteryLeft circumflex artery
- Posterior descending (posterior interventricular) artery
Detail
- Origin
- RCA in right dominance; circumflex in left dominance; both in co-dominance
- Supplies
- Inferior (diaphragmatic) LV wall, posterior third of the septum, posteromedial papillary muscle
- Dominance also decides
- Which artery gives the AV nodal artery and the posterolateral branches
When it goes wrong
Inferior MI infarcting the posteromedial papillary muscle, which has a single supply from the PDA
Papillary muscle rupture on day 2 to 7: sudden severe mitral regurgitation, flash pulmonary oedema and a new pansystolic murmur
Circumflex occlusion in a left-dominant patient
Combined lateral and inferior infarction with AV nodal ischaemia; a much larger infarct than expected from the circumflex alone
Practise this structure
1 question in the bank tagged Coronary Circulation.