1. Heart’s Crown
T h e L i v i n g P i p e s
DR. Abdul Rab Shaikh
MD Cardiology (England)
Dip Card ( London)
Consultant Invasive Cardiologist
Red Crescent Institute of Cardiology
On
Wednesday 28 th November 2012, Wednesday

2. Overview
RCA, LAD and Cx in the anterior
projection
an overview of the coronary arteries
in the anterior projection.
Left Main or left coronary artery
(LCA)
Left anterior descending (LAD)
diagonal branches (D1, D2)
septal branches
Circumflex (Cx)
Marginal branches (M1,M2)
Right coronary artery
Acute marginal branch (AM)
AV node branch
Posterior descending artery (PDA)

3. On the left an overview of the
coronary arteries in the right
anterior oblique projection.
Left Main or left coronary artery
(LCA)
Left anterior descending (LAD)
diagonal branches (D1,
D2)
septal branches
Circumflex (Cx)
Marginal branches
(M1,M2)
Right coronary artery
Acute marginal branch (AM)
AV node branch
Posterior descending artery
(PDA)

4. On the left an overview of the coronary
arteries in the lateral projection.
Left Main or left coronary artery (LCA)
Left anterior descending (LAD)
diagonal branches (D1, D2)
septal branches
Circumflex (Cx)
Marginal branches (M1,M2)
Right coronary artery
Acute marginal branch (AM)
AV node branch
Posterior descending artery (PDA)

5. left coronary artery (LCA) is also known as
the left main.
The LCA arises from the left coronary cusp.
The aortic valve has three leaflets, each
having a cusp or cup-like configuration.
These are known as the left coronary cusp
(L), the right coronary cusp (R) and the
posterior non-coronary cusp (N).
Just above the aortic valves there are
anatomic dilations of the ascending aorta,
also known as the sinus of Valsalva. The left
aortic sinus gives rise to the left coronary
artery.
The right aortic sinus which lies anteriorly,
gives rise to the right coronary artery.
The non-coronary sinus is postioned on the
right side

6. • The LCA divides almost immediately into the
circumflex artery (Cx) and left anterior
descending artery (LAD).
On the left an axial CT-image.
The LCA travels between the right ventricle
outflow tract anteriorly and the left atrium
posteriorly and divides into LAD and Cx.

7. see the main artery dividing into
• Cx with obtuse marginal branch (OM)
• LAD with diagonal branches (DB)

8. • On volume rendered images the left atrial
appendage needs to be removed to get a
good look on the LCA.

9. • In 15% of cases a third branch arises in
between the LAD and the Cx, known as the
ramus intermedius or intermediate branch.
This intermediate branche behaves as a
diagonal branch of the Cx.

10. CT image of the LAD in RAO projection
• Left Anterior Descending (LAD)
• The LAD travels in the anterior interventricular groove and continues up to the
apex of the heart.
The LAD supplies the anterior part of the septum with septal branches and the
anterior wall of the left ventricle with diagonal branches.
The LAD supplies most of the left ventricle and also the AV-bundle.
Mnemonic: Diagonal branches arise from the LAD.

11. • The diagonal branches come off the LAD and run
laterally to supply the antero-lateral wall of the left
ventricle.
The first diagonal branch serves as the boundary
between the proximal and mid portion of the LAD
(2).
There can be one or more diagonal branches: D1,
D2 , etc.

12. • Circumflex (Cx)
• The Cx lies in the left AV groove between the left atrium and left ventricle and supplies the vessels of the
lateral wall of the left ventricle.
These vessels are known as obtuse marginals (M1, M2...), because they supply the lateral margin of the
left ventricle and branch off with an obtuse angle.
In most cases the Cx ends as an obtuse marginal branch, but 10% of patients have a left dominant
circulation in which the Cx also supplies the posterior descending artery (PDA).
Mnemonic: Marginal branches arise from the Cx and supply the lateral Margin of the left ventricle.

13. • Right Coronary Artery (RCA)
• The right coronary artery arises from the anterior
sinus of Valsalva and courses through the right
atrioventricular (AV) groove between the right
artium and right ventricle to the inferior part of the
septum.
.In 50-60% the first branch of the RCA is the small
conus branch, that supplies the right ventricle
outflow tract.
.In 20-30% the conus branch arises directly from the
aorta.
.In 60% a sinus node artery arises as second branch
of the RCA, that runs posteriorly to the SA-node (in
40% it originates from the Cx).
.The next branches are some diagonals that run
anteriorly to supply the anterior wall of the right
ventricle.
.The large acute marginal branch (AM) comes off
with an acute angle and runs along the margin of
the right ventricle above the diaphragm.
.The RCA continues in the AV groove posteriorly and
gives off a branch to the AV node.
.In 65% of cases the posterior descending artery
(PDA) is a branch of the RCA (right dominant
circulation).
.The PDA supplies the inferior wall of the left
ventricle and inferior part of the septum.

14. • On the image on the far left we see the most common situation, in which the RCA
comes off the right cusp and will provide the conus branch at a lower level (not
shown).
On the image next to it, we see a conus branch, that comes off directly from the
aorta.

15. • The large acute marginal branch (AM)
supplies the lateral wall of the right ventricle.
In this case there is a right dominant
circulation, because the posterior
descending artery (PDA) comes off the RCA.

16. • Coronary anomalies are
uncommon with a prevalence
of 1%.
Early detection and evaluation
of coronary artery anomalies is
essential because of their
potential association with
myocardial ischemia and
sudden death (3).
With the increased use of
cardiac-CT, we will see these
anomalies more frequently.
• Coronary anomalies can be
differentiated into anomalies of
the origin, the course and
termination (Table).

17. • The illustration in the left upper corner is
the most common and clinically
significant anomaly.
There is an anomalous origin of the LCA
from the right sinus of Valsalva and the
LCA courses between the aorta and
pulmonary artery.
This interarterial course can lead to
compression of the LCA (yellow arrows)
resulting in myocardial ischemia.
• The other anomalies in the figure on the
left are not hemodynamically significant.

18. • Interarterial LCA
• On the left images of a patient with an anomalous origin of the LCA from the right sinus
of Valsalva and coursing between the aorta and pulmonary artery.
Sudden death is frequently observed in these patients.

19. • ALCAPA
• On the left images of a patient with
an anomalous origin of the LCA from
the pulmonary artery, also known as
ALCAPA.
ALCAPA results in the left ventricular
myocardium being perfused by
relatively desaturated blood under
low pressure, leading to myocardial
ischemia.
ALCAPA is a rare, congenital cardiac
anomaly accounting for
approximately 0.25-0.5% of all
congenital heart diseases.
Approximately 85% of patients
present with clinical symptoms of
CHF within the first 1-2 months of
life.

20. • Myocardial bridging
• Myocardial bridging is most commonly
observed of the LAD (figure).
The depth of the vessel under the
myocardium is more important that the
lenght of the myocardial bridging.
There is debate, whether some of these
myocardial bridges are hemodynamically
significant.

21. • Fistula
• On the image on the left we see a large LAD
giving rise to a large septal branch that
terminates in the right ventricle (blue
arrow).

22. Thanks