The document describes the anatomy and blood supply of the heart. It discusses the right and left coronary arteries, their branches, and the areas they supply. It also covers the conducting system of the heart, including the sinoatrial node, atrioventricular node, bundle of His, and Purkinje fibers. Additionally, it summarizes the venous drainage of the heart through coronary sinus and its tributaries.

1. Blood supply of the
Heart & Conduction
System

2. Arterial supply of Heart
 Right coronary artery
 Left coronary artery

3. Right Coronary Artery
 Arises from anterior aortic sinus of the
Ascending Aorta.
 It descends in the right atrioventricular
groove.
 Near inferior border continuous
posteriorly along the atrioventricular
groove.
 Anastomose with left coronary artery in
the posterior interventricular groove.

4. Right Coronary Artery

5. Branches of Right Coronary
Artery
1.Right conus artery:
Supplies rt ventricular outflow tract.
2.Rt marginal branch:
Supply free wall of rt ventricle.

6. Branches of Right Coronary
Artery
3. Rt posterolateral branch:
goes back of lt ventricle
supply inferior aspect of interventricular
septum
4. Atrial branches:
Supply anterior and lateral surface of the
right atrium. One branch supply posterior
surface of both right and left atria.
Artery of Sinuatrial Node (60%)

7. Branches of Right Coronary
Artery
5. Posterior interventricular (descending)
artery
 Runs towards apex in the posterior
interventricular groove.
 Supply right & left ventricles, including
its inferior wall.
 Supply posterior part of the ventricular
septum (Excluding Apex).
 Large septal branch Supply
Atrioventricular Node.

8. Clinical division of the RCA
 Proximal - Ostium to 1st main RV branch
 Mid - 1st RV branch to acute marginal
branch
 Distal - acute margin to the crux

9. Area of distribution RCA
 Rt atrium
 Greater part of rt ventricle except area
adjoining ant interventricular groove
 Small part of lt ventricle adjoining post
interventricular groove
 Whole of conducting system of heart
except part of lt branch of AV bundle
 SA Node –supplied by LCA (40%)

10. Left Coronary Artery
 Larger then Right coronary artery.
 Arises from posterior aortic sinus of the
Ascending Aorta.
 Passes between pulmonary trunk and left
auricle.
 It enters in the atrioventricular groove and
divides into an anterior interventricular
branch and a circumflex branch.
 Supply greater part of the left Atrium, left
ventricle and ventricular septum.

11. 1. Anterior interventricular (descending) artery:
 Runs in the anterior interventricular groove to
the Apex.
 Passes around the Apex to enter the posterior
interventricular groove & anastomoses with the
terminal branches of Right coronary artery.
 Supply right and left ventricles & anterior
part of ventricular septum.
 Left diagonal branch
 wrap over anterolateral free wall of lt ventricle
Septal branch curves into interventricular septum
Branches of Left Coronary
Artery

12. Left Coronary Artery

13. Branches of Left Coronary
Artery
2. Circumflex artery:
 Winds around the left margin of the heart
in the atrioventricular groove.
 obtuse marginal branch:
 supply lateral free wall of lt ventricle
 does not reach crux in pt with rt dominant
circulation
 Atrial branches: Supply left atrium.
Artery of Sinuatrial Node (40%)

14. Clinical division of the LAD
 Proximal - Ostium to 1st major septal perforator
 Mid - 1st perforator to D2 (90 degree
angle)
 Distal - D2 to end

15. Clinical division of the LCX
 Proximal - Ostium to 1st major obtuse marginal
branch
 Mid - OM1 to OM2
 Distal - OM2 to end

16. Area of distribution of LCA
 Lt atrium
 Greater Prt of lt ventricle except post
interventricular groove
 Small part of rt ventricle adjoining ant
interventricular groove
 Ant part of interventricular septum
 Lt branch of AV bundle

17. Conducting system of Heart
 S-A Node: Right coronary artery (60%)
Left coronary artery (40%)
 A-V Node and A-V Bundle: Right coronary artery
 Right Bundle branch: Left coronary artery
 Left Bundle branch: Right & Left coronary
arteries

18. Coronary segment
classification system
 CASS investigators – 27 segments
 BARI – 29 segments ( ramus intermedius
and 3rd diagonal branch)
- Obstructive CAD : > 50% stenosis

19. Cardiac dominance
 85%-rt dominant coronary artery
 8%-
 lt dominant-post descending,posterolateral lt
ventricular and AVnodal artery all supplied by
terminal portion of lt circumflex coronary
artery.rt coronary artery small and supply only rt
atrium and rt ventricle
 7%-codominant
 RCA-PDA and terminates,circumflex artery-all
post
Lt ventricular branches

20. Congenital anomaly of coronary
circulation
 Anomalous pulmary origin of coronary
artery(APOCA)
 Most common-origin of LCA from
pulmonary artery
Aortography-large RCA with absence of lt
coronary ostium in lt aortic sinus

21. Anomalous coronary artery
from opposite sinus
 Origin of LCA from rt aortic sinus
causes sudden cardiac death after exercise
in young person

22. Coronary artery fistula
 Abnormal communication between
coronary artery and major vessels such as
venacava,pulmonary artery or vein

23. Myocardial bridging
 All 3 major coronary artery generally
course along epicardial surface of heart
sometime short coronary artery segment
descend into myocardium for variable
distance
occurs in 5-12% of pt and confined to
LAD

24. Coronary artery spasm
 Dynamic and reversible occlusion of
epicardial coronary artery caused by focal
constriction of smooth muscle cell within
arterial wall
occurs in prinzmetal angina
aggrevated by cigaratte smoking,cocaine
alcohal,GA
Not aggrevated by emotion,cold

25.  Most common-separate ostium for LAD
and lcx,simillarly in RCA-conus branch may
have
Separate ostium
Origin of circumflex from rt coronary artery
RCA-originate high in aortic root

26. “Dominance”
 A misnomer
 giving rise to PDA, at least 1 PLV & AV
nodal A
(BARI classification)
- 85% right dominant
- 8% left dominant
- 7% co-dominant
(70%/ 10%/ 20% – Hurst’s THE HEART)
 Left dominance is 25-30% in Bi-AoV
Gensini GG. Coronary Arteriography. Mount Kisco,NY: Futura Publishing Co; 1975:260–274.

27. Venous Drainage of Heart
Coronary Sinus:
Runs in the coronary sulcus (posterior
atrioventricular groove).
Largest vein of heart
About 3 cm long
Ends by opening into post wall of rt
atrium
Tributaries:
 Great cardiac vein
 Middle cardiac vein

28.  Small cardiac vein
 Post vein of lt ventricle
 Oblique vein of lt atrium
 Rt marginal vein
All drains into coronary sinus which opens
into rt atrium

29. 1. Great cardiac vein-accompany ant
interventricular artery and then LCA
2. Middle cardiac vein –accompany post
interventricular artery and joins middle part of
coronary sinus
3. Small cardiac vein-accompany rt coronary
artery
4. Post vein of lt ventricle-runs on diaphragmatic

30. Surrface of lt ventricle and ends in middle of
coronary sinus
5 oblique vein of lt atrium-small vein
running on post surface of lt atrium
6 rt marginal vein-accompany marginal
branch of rt coronary artery

31. Contents of Heart grooves
1. Right atrioventricular groove:
Right coronary artery
Small cardiac vein
2. Left anterior atrioventricular groove:
Left coronary artery
3. Left posterior atrioventricular groove:
Coronary sinus
4. Anterior interventricular groove:
Anterior interventricular artery
Great cardiac vein
5. Posterior interventricular groove:
Posterior interventricular artery
Middle cardiac vein

32. Venous drainage
 Ant cardiac vein and venae cordis minimi
opens directly into rt atrium
Ant cardiac vein
3-4 small vein running parrelel to one
another on ant wall of rt ventricle
venae cordis minimi-Thebesian vein or
smallest cardiac vein
Small vein present in all chambers of heart

33. Cardiac Veins (Sternocostal Surface)
Anterior cardiac veins

34. Cardiac Veins (Diaphragmatic Surface)

35. Conducting System
 Network of
specialized
tissue that
stimulates
contraction
 Modified
cardiac
myocytes
 The heart can
contract
without any
innervation

36. The Cardiac Conduction System
The impulse conduction system of the heart consists
of four structures:
1. The sinoatrial node (SA node)
2. The atrioventricular node (AV node)
3. The atrioventricular bundle (AV bundle)
4. The Purkinje fibers
The cardiac muscle fibers that compose these
structures are specialized for impulse
conduction,rather than the normal specialization of
muscle fibers for contraction.

37. The sinoatrial node
”. SA node-located at junction of sup vena cava
and rt atrium
SA node-discharge mostrapidly,depolarisation
Spread from it to other region before they
discharge spontaneously
Its rate of dischage determine rate at which
heart beat
This is also why the SA node is said to be the
“pacemaker” of the heart

38. Spread of cardiac exitation
 Atrial activation
 Septal activation
 Activation of anteroseptal region
 Activation of major portion of ventricular
myocardium
 Activation of posterobasal portion of lt
ventricle

39. When both the
right and left atria
are completely
depolarized, they
contract
simultaneously.
Impulses from the SA node are then conducted across
the atria from right to left. The impulse does not
however pass directly to the ventricles.

40. As the atria depolarize, the impulse is picked up by
another group of specialized muscle fibers called the
atrioventricular node. The AV node is located in the
floor of the right atrium next to the interatrial septum.
This group of fibers is the only conduction pathway
between the atria and ventricles.
As the impulse is conducted through the AV node, its
speed is reduced. This is due to the extremely small
diameter of the conducting fibers.

41. This is an extremely important phenomenon because
the delay in the transmission from atria to ventricles
allows time for the atria to completely depolarize and
contract, thus emptying their contents into the still
fully relaxed ventricles.

42. From the AV node, the impulse travels down
the atrioventricular bundle. The AV bundle
divides into two lines of transmission just
below the AV node and these conduct the
impulse down the length of the interventricular
septum. An important fact about the fibers that
make up the AV bundle is that they are large in
diameter and therefore the impulse speed
increases so it is conducted very rapidly down
them.

43. About halfway down the interventricular
septum the “bundle branches” themselves begin
to branch off into enlarged conduction fibers
called Purkinje fibers. These fibers extend out
to all areas of the two ventricles and since they
are further enlarged, the speed of the impulse
conduction is also additionally increased. Upon
completion of impulse transmission through the
Purkinje fibers, the ventricles will fully
depolarize and then contract simultaneously.

44. What causes what ?
 Conduction problem in AV
NODE & HIS BUNDLE-
1st, 2nd & 3rd degree heart
blocks
 Conduction problems in
left & right bundle
branches- RBBB
LBBB
LAHB
LPHB
Bi & Tri –
fascicular
block

45. Ventricular Conduction
Disorders.
Left Bundle Branch Block.
Right Bundle Branch Block.
Other related blocks.

46. Left Bundle Branch Block.
 Block of the left bundle
or both fasicles of the
left bundle.
 Electrical potential must
travel down RBB.
 De-polarisation from
right to left via cell
transmission.
 Cell transmission longer
due to LV mass.

47. Left Bundle Branch Block (LBBB).

48. ECG Criteria for LBBB.
 QRS Duration >0.12secs.
 Broad, mono-morphic R wave leads I and
V6.
 Broad mono-morphic S waves in V1 (can
also have small 'r' wave).

49. LBBB consequence.
 Mostly abnormal ECG finding - indicates heart
disease.
 Coronary artery disease (indication for
thrombolysis - if associated with chest pain and
raised Troponin).
 Valvular heart disease.
 Hypertension.
 Cardiomegaly.
 Heart failure.
 Impacts on prognosis - QRS duration.
 Use of Bi-Ventricular Pacemakers.

50. Right Bundle Branch Block.
 Impulse transmitted
normally by left bundle.
 Blocked right bundle
results in cell
depolarisation to spread
impulse (slower).
 Impulse to IV septum
and RV delayed.
 Results in an additional
vector.

51. Right Bundle Branch Block (RBBB).

52. Additional Info RBBB.
 Can be normal.
 Sometimes related to asthma or other
airway conditions.
 Possibly due to RVH in young individuals.
 Usually due to CAD in older persons.
 Often related to congenital heart disease
(particularly ASD).
 Often apparent following cardiac surgery.

53. Left Anterior Hemi-block
Appearance.

54. ECG Features of Left Anterior
Hemi-block.
 Abnormal left axis deviation (between -30
and -900).
 Either a qR complex or an R wave in lead
I.
 rS complex in lead III (possibly also II and
aVF).
 Extremely common and un-diagnosed ECG
feature.
 NOT ALWAYS ASSOCIATED WITH BBB.

55. ECG Features Left Posterior Hemi-
block.
 Axis of 90 - 180o - (right axis).
 An s wave in lead I and a q wave in lead III.
 Exclusion of RAE or RVH.
 REMEMBER - most common cause of right
axis is RVH so this must be excluded before
you diagnose LPH.

56. Left Posterior Hemi-block.

57. INTRODUCTION TO HEART
BLOCKS
 OCCUR WHEN THERE IS A PARTIAL OR
COMPLETE INTERRUPTION IN THE
CARDIAC ELECTRICAL CONDUCTION
SYSTEM.
 CAN OCCUR ANYWHERE IN THE ATRIA
BETWEEN THE SA NODE AND THE AV
JUNCTION.
 IN THE VENTRICLES BETWEEN THE AV
JUNCTION AND PURKINJE FIBERS.
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58. FIRST-DEGREE HEART BLOCK
 DELAY OF IMPULSE BETWEEN THE ATRIA
AND BUNDLE OF HIS.
 OCCURS WHEN THERE IS A PARTIAL
INTERRUPTION ANYWHERE IN THE
ATRIAL OR AV JUNCTIONAL
CONDUCTION SYSTEM.
 THE IMPULSE IS EVENTUALLY
CONDUCTED BUT IS DELAYED.
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59. degree heart block
 Just prolongation
of PR interval.
 Normal PR 1st =
.2 Sec
 Here it is .28 Sec

60. MOBITZ I HEART BLOCK
 MOBITZ I ( WENCKEBACH OR SECOND-
DEGREE HEART BLOCK, TYPE I).
 PROGRESSIVE BLOCK.
 IMPULSE FROM THE ATRIA IS INTERRUPTED AT
THE AV JUNCTION.
 THE INTERRUPTION BECOMES LONGER WITH
EACH IMPULSE DELAYING DEPOLARIZATION OF
THE VENTRICLES UNTIL A COMPLETE
INTERRUPTION BLOCKS THE IMPULSE.
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62. MOBITZ II HEART
BLOCK
 OCCURS DUE TO AN INTERMITTENT
INTERRUPTION NEAR OR BELOW THE AV
JUNCTION.
 INTERRUPTION IS NOT PROGRESSIVE,
BUT OCCURS SUDDENLY AND WITHOUT
WARNING!!
 P WAVES BEFORE EVERY QRS COMPLEX
AND ALL ARE THE SAME SIZE AND
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64. THIRD-DEGREE HEART BLOCK
 COMPLETE HEART BLOCK OR COMPLETE
AV DISSOCIATION.
 IMPULSE IS COMPLETELY BLOCKED
BETWEEN THE ATRIA AND THE
VENTRICLES.
 USUALLY TAKES PLACE BETWEEN THE AV
JUNCTION AND BUNDLE OF HIS.
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65. Third degree heart block
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