presentation on anatomy of heart ,coronary circulation ,MI and ECG interpretations of MI by Dr.Febin Rony

1. CardiovasCular system
By
Dr.Febin Rony
BNYS

2. Cardiovascular System
It is the network of organs and elastic tubes trough which
blood flows as it carries oxygen and nutrients to all parts
of the body
Includes: The Heart & Blood vessels
Has two parts
 The Pulmonary Circulation: transports deoxygenated blood
between the heart and lungs
 The Systemic Circulation: transports oxygenated blood away from
the heart to tissues and cells, and returns oxygen back to the heart

3. BLOOD VESSELS

4. Three types
Arteries
Capillaries
Veins

5. • Carry blood away from the heart.
• “Branch” or “diverge” as they form smaller and smaller
division.
• They have Thick-walls to withstand pressure produced
when heart pushes blood into the arteries. Elastic fibers
(tunica media) allow the artery to stretch under pressure.
• Aorta: Largest artery vessels
• Arterioles: Smallest artery vessel that connect arteries to
capillaries
Pulmonary circulation
• Carry poor oxygenated blood from heart to the lungs.
Systemic circulation
• Carry rich oxygenated blood from heart to the organs and
tissues.

6. • Carry blood toward the heart.
• “Join” or “merge” into successfully larger vessels approaching
the heart.
• Have valves which act to keep the unidirectional flow blood.
• Body muscles surround the veins so that when the muscles
contract, the veins are squeeze and the blood been pushed
along the vessels.
• Vena cava: SVC (blood from upper body) & IVC (blood from
lower body) are the biggest veins.
• Venules: Smallest vein vessels that connect veins to
capillaries
Pulmonary circulation
• Carry rich oxygenated blood from lungs to the heart
Systemic circulation
• Carry poor oxygenated blood from other parts of body to the
heart

7. • Connect arteries and veins.
• Contact tissue cells and directly serve cellular needs.
• Exchange between blood and tissue cells occurs in them.
• Exchange:
• Drop off oxygen and nutrients from heart by arteries
• Pick up CO2 and other waste products and send to heart
by veins.
• Walls are one cell thick and very narrow.

8. The Heart
It Is made up of cardiac muscle fibers
 Average beat is 60-100 bpm,pumping 8,000 liters each day.
Each time the cardiac muscle contracts, blood pushes through
the body within blood vessels
About the size of a fist, shaped like an up-side-down pear.
Located
 In the mediastinum between the lungs
 On the superior surface of diaphragm
 ⅔’s of it lies to the left of the midsternal line
 Anterior to the vertebral column, posterior to the sternum
• It is approximately the size of your fist weighing aroundIt is approximately the size of your fist weighing around
250-300 grams covered in the pericardium.250-300 grams covered in the pericardium.
• It helps in the transport of Nutrients, waste pdts and Regulate
Temp.,Water balance ,Acid-Base Balance & Immunity.

9. ANATOMY OF HEART
Figure 18.1

10. PERICARDIUM :Coverings of the Heart
Pericardium is a double-layered sac around
the heart.
Confines heart to the mediastinum
Allows sufficient freedom of movement.
Protects and anchors the heart
Allows the heart to move in a friction-free
environment.
Layers of pericardium are
fibrous pericardium
serous pericardium
parietal layer
visceral layer or epicardium
Serous pericardium and epicardium are separated by
the fluid-filled cavity called the pericardial cavity.

11. Pericardial Layers of the Heart

12. Layers of the Heart Wall
 Epicardium – visceralEpicardium – visceral
pericardiumpericardium
 Myocardium – cardiacMyocardium – cardiac
muscle layer formingmuscle layer forming
the bulk of the heartthe bulk of the heart
 Endocardium –Endocardium –
endothelial layer of theendothelial layer of the
inner myocardialinner myocardial
surfacesurface

13. • External markings
• Apex - pointed inferior region
• Base - upper region
• Coronary sulcus
• Indentation that separates atria from ventricles
• Anterior and posterior interventricular sulcus
• Separates right and left ventricles
FEATURES

14. Internal divisions
Atria (superior) and ventricles (inferior)
Interventricular and interatrial septa

15. Atria of the Heart
Atria - receiving chambers of the heart
Receive venous blood returning to heart
Separated by an interatrial septum (wall)
 Foramen ovale - opening in interatrial septum in fetus
 Fossa ovalis - remnant of foramen ovale
Each atrium has a protruding auricle
They pump blood into ventricles
Blood enters right atria from superior and
inferior venae cavae and coronary sinus
Blood enters left atria from pulmonary
veins

16. Gross Anatomy of Heart: Frontal
Section
Figure 18.4e

17. Ventricles of the Heart
 Ventricles are the discharging chambers of the heart
 Papillary muscles and trabeculae carneae muscles mark
ventricular walls
 Separated by an interventricular septum
 Contains components of the conduction system
 Right ventricle pumps blood into the pulmonary trunk and it is
a much low pressure system requiring less energy output by
ventricle
 Left ventricle pumps blood into the aorta
 Has thicker(3 times) myocardium due to greater work load

18. Heart valves ensure unidirectional blood flow
through the heart
They are 2 Atrio-ventricular valves & 2
HEART VALVES

19. Atrioventricular (AV) valves lie between the atria and the
ventricles
R-AV valve = tricuspid valve
L-AV valve = bicuspid or mitral valve
AV valves prevent backflow of blood into the atria when
ventricles contract
Chordae tendineae anchor AV valves to papillary
muscles of ventricle wall
 Semilunar valves prevent backflow of blood into the
ventricles
 Aortic semilunar valve lies between the left ventricle and the
aorta
 Pulmonary semilunar valve lies between the right ventricle and
pulmonary trunk
Fibrous Skeleton Surrounds all four valves Composed of
dense connective tissue. They anchors valve cusps and
prevents over dilation of valve openings.

21. HEART: ANTERIOR VIEW
Figure 18.4b

22. Heart: Posterior View
Figure 18.4d

23. CARDIAC CYCLE
0.8 seconds

24. SYSTOLE DIASTOLE
CARDIAC CYCLE
1) Isometric contraction
0.05 seconds
2) Ejection period
0.22seconds
 Total 0.27 seconds
1.Protodiastole 0.04 sec.
2.Isometric relaxation 0.08s
3.Rapid filling 0.11s
4.Slow filling 0.19s
5.Last rapid filling 0.11s
 Total 0.53 seconds
Cardiac cycle is total 0.8seconds

25. SYSTOLE-0.27s.
Atria contract and small amount of blood enters
ventricles.
ISOMETRIC CONTRACTION-0.5s.
All valves closed. Ventricles undergo isometric
contraction and pressure in the ventricles is
increased
EJECTION PERIOD-0.22s
Semilunar valves are opened ventricles contracts
and blood is ejected out
DIASTOLE-0.53S.
RAPID AND SLOW FILLING-0.3s.
Atrioventricular valves are opened. Ventricles
undergo isometric relaxation and pressure in
ventricles is reduced.
ISOMETRIC RELAXATION-0.08s.
All valves are closed and pressure in the
ventricles is reduced.
PROTODIASTOLE-0.04s.
First stage of diastole. The semilunar valves are
closed at the end of this period.

26. HEART SOUNDSHEART SOUNDS
PRODUCED FROM BLOODPRODUCED FROM BLOOD
TURBULENCE CAUSED BY CLOSINGTURBULENCE CAUSED BY CLOSING
OF HEART VALVES.OF HEART VALVES.
S1 – ATRIOVENTRICULAR VALVES1 – ATRIOVENTRICULAR VALVE
CLOSURECLOSURE
S2 – SEMILUNAR VALVE CLOSURES2 – SEMILUNAR VALVE CLOSURE
S3 – RAPID VENTRICULAR FILLINGS3 – RAPID VENTRICULAR FILLING
S4 – ATRIAL SYSTOLES4 – ATRIAL SYSTOLE

27. THE CONDUCTION SYSTEM
 Formed by the modified cardiac
muscle fibers. They conduct
impulses from SA node to ventricles
 These fibers have 2 important
function
 Act as pace maker
 Form the conduction system
 SA node would initiates action
potential about every 0.6 sec or 100
times/min.
 the ANS alters the strength and
timing of heart beats.

28. PHYSIOLOGIC
CHARACTERISTICS OF THE
CONDUCTION CELLS
AUTOMATICITY
EXCITABILITY
CONDUCTIVITY
RHYTHMICITY
CONTRACTILITY
TONICITY

29. Coronary Circulation
CONSIST OF
•1) Arterial supply
•2) Venous drainage
•3) Lymphatic drainage

30. ARTERIAL SUPPLY
• The cardiac muscle is supplied by two coronary
arteries the right and left coronary arteries.
• Both arteries arises from the sinuses behind the
cusps of the aortic valves at the root of the aorta.

31. RT. CORONARY ARTERY
Smaller than left coronary artery.
•Arises from anterior coronary sinus.
COURSE:
•Emerges from the surface of heart between pulmonary
trunk and right auricle.
•Winds round the inferior border to reach the
diaphragmatic surface to reach the posterior inter-
ventricular groove.
•Terminates by anastomising with left
coronary artery
BRANCHES
•Large Branches
• marginal
• Post-inter ventricular
•Small branches:
• Right atrial
• Infundibular
• Nodal – in 60% cases
• Terminal

32. Anterior schematic diagram of heart shows course of dominant right coronary artery and its
tributaries. AV = atrioventricular, PDA = posterior descending artery, RCA = right coronary artery,
RV = right ventricular, SA = sinoatrial

33. AREAS OF DISTRIBUTION
•Right atrium
•Ventricles
• Greater part of right ventricle, except the
area adjoining the anterior inter-ventricular
groove.
• A small part of the left ventricle adjoining
the posterior interventricular groove.
•Posterior part or the inter-ventricular septum
•Whole of the conducting system of the heart
except a part of the left branch of AV bundle.
The SA node is supplied by left coronary
artery in 40% cases

34. LEFT CORONARY ARTERY
Larger than the right coronary artery.
•Arises from left posterior aortic sinus.
COURSE
•Runs forward and to the left and emerges
between the pulmonary trunk and the left
auricle.
•Here the anterior inter-ventricular branch is
given .
•The further continuation of the left coronary
artery is sometimes called the circumflex
artery.
•After giving off the anterior inter ventricular
branch it runs into the left anterior coronary
sulcus.
•It winds around the left border and near
posterior inter ventricular groove it terminates
by anastomosing with the right coronary
artery.

35. BRANCHES:
•Large Branches:
• Anterior interventricular
• Branch to the diaphragmatic surface of the left
ventricle
•Small Branches:
― Left atrial
― Pulmonary
― Terminal

36. Dominant left coronary artery anatomy. Left anterior oblique schematic diagram of dominant left
coronary artery anatomy, including left anterior descending artery and left circumflex artery
tributaries, is shown. AVGA = atrio ventricular groove artery, PDA = posterior descending artery.

37. Areas of distribution
•Left atrium
•Ventricles:
−Greater part of left ventricle, except the area
adjoing the posterior interventricular groove.
−A small part of right ventricle adjoining the anterior
interventricular groove.
•Anterior part of interventricular septum.
•Part of left branch of AV bundle

38. COLLATERAL CIRCULATION
• Cardiac anatomosis: The two coronary arteries
anastomose in the myocardium.
• Extra cardiac anastomosis: The coronary arteries
anastomose with the
• Vasa vasorum of the aorta,
• Vasa vasorum of pulmonary arteries,
• Internal thoracic arteries
• The bronchial arteries
• Phrenic arteries.
• These channels open up in the emergencies when the
coronary arteries are blocked.

39. CORONARY ARTERY DOMINANCE
•The artery that gives the posterior interventricular artery determines
the coronary dominance.
•If the posterior interventricular artery is supplied by the right coronary
artery (RCA), then the coronary circulation can be classified as "right-
dominant".
•If the posterior interventricular artery is supplied by the circumflex
artery (CX), a branch of the left artery, then the coronary circulation can
be classified as "left-dominant".
•If the posterior interventricular artery is supplied by both the right
coronary artery (RCA) and the circumflex artery, then the coronary
circulation can be classified as "co-dominant".

40. VENOUS DRAINAGE OF THE HEART
• The venous drainage of the
heart is by three means:
• Coronary sinus.
• Anterior cardiac veins
• Venae Cordis minimae.

41. CORONARY SINUS
•This is the largest of vein of heart situated in the left
posterior coronary sulcus. It is about 3 cm long and ends
by opening into the posterior wall of the right atrium.
•Its tributaries are:
−Great cardiac vein: It enters the left end of the
coronary sinus.
−Middle cardiac vein: It accompanies the
posterior inter ventricular artery and joins the
right end of the coronary sinus.
−Small cardiac vein: It accompanies the right
coronary artery and joins the right end of the
coronary sinus.

42. −Posterior vein of left ventricle: It runs on the
diaphragmatic surface of the left ventricle and ends in
the middle of the coronary sinus.
−Oblique vein of left atrium : It runs on the posterior
surface of the left atrium, joins the left end of
coronary sinus and develops from the left common
cardinal vein.
−The right marginal vein: It accompanies the marginal
branch of the right coronary artery.

43. ANTERIOR CARDIAC VEIN
3 to 4 small veins run on the anterior wall of
the right ventricle, open directly into the right atrium.
VENAE CORDIS MINIMAE
(also called smallest cardiac veins, venae cardiae
minimae, or Thebesian veins)
•Numerous small veins present in all 4 chambers of
heart which open directly into the cavities.
•The Thebesian venous network is considered an
alternative (secondary) pathway of venous drainage
of the myocardium. It is named after German
anatomist Adam Christian Thebesius , who
described them.

44. PECULIARITIES OF COR.CIRCULATION
• Blood Flow during diastole
• End arteries
• High capillary density
• Anatomical anastomosis
• The coronary vessels are susceptible to degeneration and
atherosclerosis.
• There is evident regional distribution: The subendocardial myocardial
layer in the left ventricle receives less blood, due to more myocardial
compression (but this is normally compensated during diastoles by
V.D). However, this renders this area more liable to ischemia and
infarction.
• The resting coronary blood flow is about 225 ml/min., which is
about 0.7 – 0.8 ml/gm of heart muscle, or 4- 5 % of the total
cardiac output. In severe muscular exercise, the work of the
heart increased and the CBF may be increased up to 2 liters/
minute.

45. Applied Aspects of
coronAry
circulAtion

46. MYOCARDIAL INFARCTION & ECG in MI
 MYOCARDIAL INFARCTION means necrosis of a part of the
myocardium due to
− Severe & prolonged ischemia due to narrowing of the coronary arteries.
− Occlusion of one of the coronary arteries or its branches by coronary
thrombosis → severe ischemia.
 Myocardial Infarction produces also chest pain which is more
severe than that of angina and it cannot be relieved by rest or
coronary VD drugs.
 ECG is the technique by which the electrical activities of the
heart is recorded for diagnosing various conditions.
 This technique was discovered by Dutch physiologist
Einthoven William and he is considered as father of ECG.

47.  The machine receives impulses by placing electrodes from the
body Electrocardiograph or an ECG machine amplifies the
electrical signals produced by the heart and records these
signals on a moving ECG paper.
 They are placed on the right arm , left arm and left leg the
heart is said to be in the center of this imaginary equilateral
triangle called EINTHOVEN’S Triangle.
 BIPOLAR LEADS /Standard limb leads- Has three standard
limb leads .
1. Lead I – right arm (-ve) to left arm(+ve)
2. Lead II – right arm (-ve) to left leg (+ve)
3. Lead III – left arm (-ve) to left leg (+ve)
 Unipolar leads
I. Unipolar limb leads/ Augmented limb leads
II. Unipolar chest leads/ Precardial leads
E C G

48. The 12-Leads
The 12-leads include:
 3 Limb leads
(I, II, III)
 3 Augmented leads3 Augmented leads
(aVR, aVL, aVF)(aVR, aVL, aVF)
 6 Precordial leads
(V1- V6)
The machine receives impulses by placing electrodes on the body

49. ECG Basics
How to Analyze a Rhythm
Normal Sinus Rhythm
Heart Arrhythmias
Diagnosing a Myocardial Infarction
Advanced 12-Lead Interpretation

50. Basic laws of ECG
If the impulse(vector/current) moving towards the
positive pole of a lead it will create a +ve
deflection in that lead

51. Law of Continuation
• If the impulse (vector/current) is moving away from
the positive pole (towards negative pole) it will
create a negative deflection in that lead

52. Precceds QRS complex
Amplitude 2- 2.5 mm
Duration 0.06- 0.11
Configuration :usually rounded
and upright
L 1 - + ve (Upright
L 2 - +ve
L3 - Usually +ve
AVR - Usually – ve
AVL - Usually +ve
AVF - +ve
VI - Biphasic (variable)
V1- V6- +ve

54. Normal Impulse Conduction
Sino-atrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers

55. Impulse Conduction & the ECG
Sino atrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers

56. The “PQRST”
P wave - Atrial depolarization
• T wave – Ventricular repolarization
• QRS – Ventricular depolarization

57. The PR Interval
Atrial depolarization
+
delay in AV junction
(AV node/Bundle of His)
(delay allows time for the atria to
contract before the ventricles
contract)

58. Pacemakers of the Heart
 SA Node - Dominant pacemaker with an intrinsic rate of 60 - 100
beats/minute.
 AV Node - Back-up pacemaker with an intrinsic rate of 40 - 60
beats/minute.
 Ventricular cells - Back-up pacemaker with an intrinsic rate of 20
- 45 bpm.

59. The ECG Paper
 Horizontally
 One small box - 0.04 s
 One large box - 0.20 s
 Vertically
 One large box - 0.5 mV

60. The ECG Paper (cont)
 Every 3 seconds (15 large boxes) is marked by a vertical line.
 This helps when calculating the heart rate.
NOTE: the following strips are not marked but all are 6 seconds
long.
3 sec 3 sec

61. ECG Rhythm
Interpretation
How to Analyze a Rhythm

62. Rhythm Analysis
 Step 1: Calculate rate.
 Step 2: Determine regularity.
 Step 3: Assess the P waves.
 Step 4: Determine PR interval.
 Step 5: Determine QRS duration.

63. Step 2: Determine regularity
Look at the R-R distances (using a caliper or
markings on a pen or paper).
Regular (are they equidistant apart)?
Occasionally irregular? Regularly irregular?
Irregularly irregular?
Interpretation? Regular
R R

64. Step 3: Assess the P waves
Normal P waves with 1 P
wave for every QRS

65. Step 4: Determine PR interval
 Normal: 0.12 - 0.20 seconds.
(3 - 5 boxes)
Interpretation? 0.12 seconds

66. Step 5: QRS duration
 Normal: 0.04 - 0.12 seconds.
(1 - 3 boxes)
Interpretation? 0.08 seconds

67. Rhythm Summary
Rate 90-95 bpm
Regularity regular
P waves normal
PR interval 0.12 s
QRS duration 0.08 s
Interpretation? Normal Sinus Rhythm

68. Diagnosing a MI and it’s location

69. ST Elevation
One way to
diagnose an
acute MI is to
look for
elevation of the
ST segment.

70. ST Elevation (cont)
Elevation of the ST segment
(greater than 1 small box) in
2 leads is consistent with a
myocardial infarction.

71. ST Elevation Infarction
Here’s a diagram depicting an evolving infarction:
A. Normal ECG prior to MI
B. Ischemia from coronary artery occlusion results
in ST depression (not shown) and peaked T-
waves
C. Infarction from ongoing ischemia results in
marked ST elevation
D/E. Ongoing infarction with appearance of
pathologic Q-waves and T-wave inversion
F. Fibrosis (months later) with persistent Q- waves,
but normal ST segment and T- waves

72. Locations of MI
Now that you know where to look for an anterior wall myocardial infarction
let’s look at how you would determine if the MI involves the lateral wall or
the inferior wall of the heart.

73. How to determine the
location of the Infarction.
Using the 12 leads of the ECG

74. Anterior Myocardial Infarction
If you see changes in leads V1 - V4 that
are consistent with a myocardial
infarction, you can conclude that it is an
anterior wall myocardial infarction.

75. i.e., the 12-leads of the ECG look at different portions of
the heart. The limb and augmented leads “see” electrical
activity moving inferiorly (II, III and aVF ), to the left (I,
aVL ) and to the right ( aVR ). Whereas, the precordial
leads “see” electrical activity in the posterior to anterior
direction.
Limb Leads Augmented Leads Precordial Leads

76. Anterior MI
Remember the anterior portion of the heart is
best viewed using leads V1- V4.
Limb Leads Augmented Leads Precordial Leads

77. Antero- Septal Wall
 V1, V2
 Along sternal borders
I
II
III
aVR
aVL
aVF
V1
V2
V3
V4
V5
V6
(LAD)

78. Anterior Wall
 V3, V4
 Left anterior chest
I
II
III
aVR
aVL
aVF
V1
V2
V3
V4
V5
V6
(LAD)

79. ECG of anterior Myocardial Infarction

80. Lateral MI
The lateral portion of the
heart is best viewed in the
Limb Leads Augmented Leads Precordial Leads
Leads I, aVL , and V5- V6

81. Lateral Wall
• I and aVL
– Left Arm
I
II
III
aVR
aVL
aVF
V1
V2
V3
V4
V5
V6
(Circumflex)

82. Lateral Wall
• V5 and V6
– Left lateral chest
I
II
III
aVR
aVL
aVF
V1
V2
V3
V4
V5
V6
(Circumflex: Branches from LAD)

83. Lateral
Lateral Wall
• I, aVL, V5, V6
I
II
III
aVR
aVL
aVF
V1
V2
V3
V4
V5
V6
(Circumflex)

84. Anterolateral MI
This person’s MI involves both the anterior wall
(V2-V4) and the lateral wall (V5-V6, I, and aVL)!

85. Inferior MI
The inferior portion of the
heart is best viewed in
Limb Leads Augmented Leads Precordial Leads
Leads II, III and aVF

86. Inferior Wall
Inferior Wall
I
II
III
aVR
aVL
aVF
V1
V2
V3
V4
V5
V6
(RCA)

87. Inferior Wall MI
This is an inferior MI. Note the ST elevation in leads II, III and aVF.

88. Anterior Wall MI
Location Reflecting Leads Probable Vessels
Anterior V3 & V4 LAD
Antero-septal V1 - V4 LAD
Lateral I, aVL, & V6 LCX, LAD
Anterolateral I, aVL, & V3 - V6 LAD, LCX
Extensive Anterior I, aVL, & V1 - V6 L. Main, LAD, LCX
High Lateral I & aVL LCX, LAD
Inferior MI
Inferior II, III, aVF RCA
Infero-lateral II, III, aVF, I, aVL, V5-6
Posterior MI
Posterior V1 - V3 (ST depression early)
(R-wave late) RCA, LCX
In short theLocating Myocardial Infarction and Probable Vessels Involved

89. Reference
• Essentials of medical physiology by
K.Sembulingam.
• Text book of anatomy by BD Chaurasia
• Grey’s Atlas of anatomy

90. THANK youTHANK you