Cardiac anatomy

Question 1

Describe the anatomy of the coronary artery system

Answer 1

The left coronary artery originates from the left coronary ostium as the left main stem and divides early into the left anterior descending artery (also known as the anterior interventricular artery) and circumflex artery .

• The right coronary artery originates from the right coronary ostium and eventually terminates as the posterior descending artery (also known as the posterior interventricular artery) and posterior left
  ventricular artery .

Question 2

Describe the anatomy of the left main coronary artery

Answer 2

The left main coronary artery (left main stem) courses from the left coronary sinus of the aorta in an anterior and inferior direction between the pulmonary trunk and the left atrial appendage.
It then divides into two major arteries of nearly equal diameter, the left anterior descending artery and the circumflex artery. Typically, no
branches are seen before this bifurcation.
In some patients, the left main coronary artery trifurcates into the intermediate coronary artery (ramus intermedius), left anterior descending artery and circumflex artery.
The left main coronary artery is typically 10-40mm in length but may be absent in patients with separate circumflex and left anterior descending coronary ostia.

Question 3

what is length and diameter of LMS

Answer 3

10 to 40 mm length
4 to 5mm diameter

Question 4

Describe the anatomy of the left anterior descending
(LAD) artery

Answer 4

The LAD artery courses anteriorly and inferiorly in the anterior interventricular groove towards the apex of the heart.
Occasionally, the LAD continues around the apex to supply part of the posterior interventricular groove and rarely even replaces the posterior descending artery.

In 4% of patients, the LAD bifurcates proximally and continues as two
equal sized parallel vessels down the anterior interventricular groove.

Question 5

branches of LAD

Answer 5

1) diagonal arteries (usually 2-6 in number) which course along
and supply the anterolateral wall of the left ventricle;
2) septal perforator arteries (usually 3-5 in number) which branch perpendicularly into and supply the anterior two thirds of the ventricular septum. The first septal artery is the largest and
runs perpendicularly towards the medial papillary muscle of the tricuspid valve. It is at risk during the Ross procedure as it lies immediately beneath the right ventricular outflow tract and pulmonary valve;
3) right ventricular branches, which supply blood to the anterior surface of the right ventricle but are not always present.

Question 6

segments of LAD

Answer 6

a proximal third, which runs from the origin of the LAD to the
origin of the first septal artery;
b) a middle third, which runs from the first septal artery to the

   origin of the last diagonal artery; c) a distal third, which runs from the last diagonal artery to the termination of the LAD

Question 7

importance of first septal artery

Answer 7

can be damaged during ross procedure as it runs towards medial papillary muscle of tricuspid valve and lies just beneath RVOT and Pulmonic valve

Question 8

in what percentage of people LAD divides into two parallel branches.

Answer 8

4 percent

Question 9

Describe the course of the circumflex coronary artery

Answer 9

The circumflex coronary artery courses along the left atrioventricular
groove and in 85-90% of patients terminates before reaching the
posterior interventricular groove. In 10-15% of patients, the circumflex
coronary artery continues as the posterior descending artery.

Question 10

branches of LCx

Answer 10

1) obtuse marginal arteries that supply the lateral aspect of the
left ventricular wall, including the anterolateral papillary muscle
of the mitral valve;
2) left atrial branches;
3) sino-atrial nodal artery (in 45% of patients);
4) atrioventricular nodal artery (in 10-15% of patients);
5) posterior descending artery (in 10-15% of patients)

Question 11

LCx supplies SA node ..percentage

Answer 11

45%

Question 12

LCx supplies AV node

Answer 12

10 to 15%

Question 13

LCx supplies PDA

Answer 13

10 to 15%

Question 14

anatomy of RCA

Answer 14

The RCA courses anteriorly and laterally from its origin at the right coronary ostium, descending into the right atrioventricular groove and inferiorly towards the acute margin of the right ventricle.
* It courses around to the inferior surface of the heart and after giving off the posterior descending artery, it continues as the posterior left ventricular artery.

Question 15

branches of RCA

Answer 15

1) sino-atrial nodal artery (in 55% of patients) (see below);
2) infundibular (or conus) branch that courses anteriorly over the
right ventricular infundibulum;

3) acute marginal branch that courses over the acute margin of
the right ventricle;

4) anterior right ventricular branches that supply the anterior free wall of the right ventricle;

5) atrioventricular nodal artery (in 85-90% of patients) (see
below);

6) posterior descending artery (in 85-90% of patients), which
runs in the posterior interventricular groove and gives off septal perforator arteries which branch perpendicularly into and supply the posterior one third of the ventricular septum;

g) posterior left ventricular artery that supplies the posterior surface of the left ventricle.

Question 16

blood supply of SA node, AV node and PDA

Answer 16

55% rt 45 % lt …80-85% rt ,,80-85%rt