Coronary Circulation & Conduction System Flashcards
what are the 5 key physiological features of the heart
chronotropy dromotropy (conduction) bathmotropy (excitability) ionotropy (contractility) Lusitropy (relaxation)
blood supply to the heart tissue
supplied by coronary arteries and their branches
Right coronary artery (RCA)
Left coronary artery (LCA)
where does the endocardium receive oxygen and nutrients from
the chambers of the heart
what and where are the coronary arteries
the only branches of the ascending aorta and they emerge in the aortic sinuses
what happens to the aortic sinus during systole
they fill up which means that coronary arteries also fill up
during systole they are blocked off as the valves are pushed open
RCA
arises from the right aortic sinus
- has a SA nodal branch, supplies the node of the conduction system
- its atrial branches supply the right atrium
- the right (acute) marginal branch
- usually gives off posterior inter ventricular branch (aka posterior descending artery)
- anastomoses with branches of left coronary artery in the artery sulcus at the apex
LCA
arises from the left aortic sinus between the left auricle and the pulmonary trunk
- shorter but thicker than the RCA
- enters the coronary sulcus and divides into the circumflex and the anterior interventricular branches (LAD)
LAD - left anterior inter ventricular descending artery (2nd branch of the LCA)
- supplies the sternocostal surface
- anasomoses with posterior inter ventricular branch of the RCA at the apex
- artery of sudden death, as when it gets blocked it causes instant death
circumflex branch of the LCA
branches to the left (obtuse) marginal branch which anastomoses with the branches of the RCA
RCA and its branches supply
- the walls of the RA and RV
- SA and AV nodes
- Posterior part of the inter ventricular septum (the proximal portion of the bundle of His)
- Small areas of the walls of LA and LV
LCA and its branches supply
- Walls of LA and LV
- most of the atrioventricular septum including part of the AV bundle
CORONARY DOMINANCE
✓ The artery that gives off the posterior interventricular/posterior descending artery determines the coronary dominance
✓ In ~80% of the people RCA is dominant
If both are involves it is called coronary co-dominance
Where and what is the likelihood of a myocardial infarction happening in what artier
LAD - 40-50%
RCA - 30-40%
Circumflex 15-20%
what damage could of myocardial infarction do to the conducting system
if its in the LAD = it supplies the AV bundles
RCA supplies both the SA and AV nodes
Heart block can cause bradycardia
Coronary Artery Bypass Grafting (CABG)
this bypasses the occluded portion of the vessel using the internal thoracic artery