Anaethesia and Cardiology Seminar Presentation at GRMC Gwalior

1. ANATOMY, INNERVATION,
CONDUCTION AND CIRCULATION OF
THE HEART, GREAT VESSELS &
CORONARY CIRCULATION
Presented by
Dr. Sandeep Singh Jadon
MBBS MD Anaesthesiology
G.R.M.C. Gwalior

2. THE HEART
• Hollow , muscular organ of a somewhat conical form lie between the lungs in the
mediastinum and is enclosed in the pericardium.
• Weighs 250 g in females and 300 g in males
• 12 cm in length, 9 cm in width; about the size of clenched fist.
• Layers:
Endocardium
Myocardium
Epicardium
Pericardium(parietal and visceral)

3. COVERINGS AND LAYERS OF HEART
WALL
• The fibrous pericardium forms a thick
outer layer of connective tissue.
• The parietal pericardium is a
serous membrane attached directly to
the fibrous layer.
• A visceral pericardium is a serous
membrane that forms the outer layer of
the heart wall.
Epicardium – visceral layer of the serous pericardium
Myocardium – cardiac muscle layer forming the bulk of the
heart
Fibrous skeleton of the heart – crisscrossing, interlacing
layer of connective tissue
Endocardium – endothelial layer of the inner myocardial

4. PERICARDIUM
BLOOD SUPPLY
Fibrous and parietal pericardium supplied by:
 Internal thoracic artery
 Musculophrenic arteries
 Descending thoracic aorta
NERVE SUPPLY
• Fibrous pericardium & parietal pericardium are supplied by the phrenic
nerve.
• They are sensitive to pain.
• Hence, pain of pericarditis originates from parietal pericardium.
• Visceral pericardium supplied by autonomic nervous system. Insensitive to
pain.

5. EXTERNAL FEATURES OF THE HEART
GROOVES OR SULCUS:
1. Atrioventricular or Coronary
sulcus – consists of anterior and
posterior parts
2. Interatrial Groove – overlapped
by descending aorta and
pulmonary trunk
3. Posterior interventricular groove
4. Anterior interventricular groove

6. EXTERNAL FEATURES OF THE HEART
APEX:
• Formed entirely by the left ventricle
• Situated 9 cm lateral to mid-sternal line
and just medial to midclavicular line
BASE:
• Also called posterior surface
• Mainly comprises of left atrium
• Four pulmonary veins open into the base
• Extends from T5 to T8 vertebral column

7. EXTERNAL FEATURES OF THE HEART
BORDERS:
• Superior border: formed by the two atrias
• Right border: formed by the right atria,
extending from SVC to IVC
• Left border: formed by left ventricle,
extending from left atrium to apex
• Inferior border: formed by right ventricle,
extending from IVC to apex

8. EXTERNAL FEATURES OF THE HEART
SURFACES
1. Anterior or Sternocoastal surface:
formed mainly by right atrium and right
ventricle
2. Inferior or diaphragmatic surface: rests
on central tendon of diaphragm. Left 2/3
rds formed by left ventricle & right 1/3rds
formed by right ventricle
3. Left surface: formed by left ventricle
4. Posterior surface or base

9. RIGHT ATRIUM
Receives blood from the
entire body and pumps it
into the right ventricle via
atrioventricular valve or
tricuspid valve
Tributaries:
1. Superior vena cava
2. Inferior vena cava
3. Coronary sinus
4. Anterior cardiac veins
5. Venae cordis minimi
(thebesian veins)
6. Sometimes the right
cardinal vein
SA node lies in the upper part
of a vertical groove in the right
atrium, called sulcus
terminalis

10. RIGHT VENTRICLE
Receives blood from the right
atrium and pumps it to the lungs
through the pulmonary trunk and
pulmonary arteries
Consists of two parts:
1. Inflowing part – Rough due to
presence of muscular ridges
called trabeculae carneae
2. Outflowing part – also called
infundibulum is smooth
Pillars or Papillary muscles:
• One end attached to ventricular
wall & the other end attached to
the cusps of tricuspid valve via
chordae tendinae
• There are 3 papillary muscles:
anterior, posterior and septal
Septomarginal trabeculae
or Moderator band:
• Is a muscular ridge
extending from the
ventricular septum to the
base of anterior pillar
muscles
• Contains right branch of AV
Bundle

12. LEFT ATRIUM
Receives oxygenated blood from
the lungs through four pulmonary
veins, and pumps it to the left
ventricle through the left
atrioventricular valve or bicuspid
valve or mitral valve

13. LEFT VENTRICLE
Receives oxygenated blood from
the left atrium and pumps it to the
aorta
Consists of two part:
1. Lower rough part with trabeculae
carneae
2. Upper smooth part or the aortic
vestibule gives origin to the
ascending aorta
Contains two well developed papillary
muscles, anterior and posterior. Chordae
tendinae from both muscles are attached
to both the cusps of the mitral valve

15. RIGHT ATRIUM VS LEFT ATRIUM
RIGHT ATRIUM
1. Receives venous blood of the
body
2. Pushes blood to right ventricle via
tricuspid valve
3. Forms right border, part of
sternocoastal surface and small
part of the base of the heart
4. Enlarged in tricuspid stenosis
LEFT ATRIUM
1. Receives oxygenated blood from
lungs
2. Pushes blood to the left ventricle
via biscuspid valve
3. Forms major part of the base of
the heart
4. Enlarged in mitral stenosis

16. LEFT VENTRICLE VS RIGHT VENTRICLE
LEFT VENTRICLE
1. Three times thicker than right
ventricle
2. Pushes blood to the entire body
3. Contains two strong papillary
muscles
4. Cavity is circular
5. Contains oxygenated blood
RIGHT VENTRICLE
1. One-third the size of left ventricle
2. Pushes blood to the lungs only
3. Contains three small papillary
muscles
4. Cavity is crescentic
5. Contains deoxygenated blood

17. SUPERIOR VENA CAVA
Collects
deoxygenated blood
from the head and
neck, upper limbs and
thorax, and drains it
into the right atrium.
And is approx. 7 cms
long
Formed by the union of the
right and the left
brachiocephalic veins just
behind the lower border of
the 1st right coastal cartilage
close to the sternum
Brachiocephalic vein is formed by the union of
internal jugular vein & subclavian vein

18. Tributaries
1. Azygous veins: opens
at the level of 2nd
coastal cartilage
2. Several small
mediastinal and
pericardial veins drains
into the vena cava

19. The inferior vena cava (IVC) is the largest vein of the human body.
It is located at the posterior abdominal wall on the right side of the aorta.
Formed by union of two common illiac vein(L5).
Piearces central tendon of diaphragm at level of T8 and open in the right atrium at level of right 6th
costal cartilage.
The IVC’s function is to carry the venous blood from the lower limbs and abdominopelvic region to
the heart
INFERIOR VENA CAVA

21. AORTA
Carries oxygenated
blood from the left
ventricle and
distributes it to the
entire body
Consists 3 parts:
1. Ascending aorta
2. Arch of aorta
3. Descending aorta

22. ASCENDING AORTA
Origin:
Arises from the upper end of
the left ventricle, at the left
half of the sternum at the level
of lower border of the 3rd
coastal cartilage
Approx 5 cms long &
enclosed in the pericardium
Runs upwards , forwards
and to the right and
becomes continuous with
the arch of aorta
There are 3 dilations at the
root of the aorta termed as
sinuses.
There are 3 sinuses: anterior,
left posterior and right
posterior
Branches:
1. Right coronary artery –
arising from anterior aortic
sinus
2. Left coronary artery –
arising left posterior aortic
sinus

23. ARCH OF AORTA
Continuation of
ascending aorta
Situated in the
superior mediastinum
behind the lower half
of the manubrium
sterni
Begins from the upper
border of the 2nd right
sternocoastal joint
Ends at the lower border
of the body of the 4th
thoracic vertebrae
Continues as descending
thoracic vertebrae
Branches:
1. Brachiocephalic artery
2. Left common carotid
artery
3. Left subclavian artery

24. DESCENDING AORTA
DESCENDING
THORACIC AORTA
DESCENDING
ABDOMINAL AORTA
• Lies in the posterior mediastinum
• It is the continuation of the arch of
aorta
• Ends at the lower end 12th thoracic
vertebrae
• Branches :
1) 9 posterior intercoastal arteries
2) subcoastal artery on each side
3) 2 left bronchial arteries
4) Oesophageal branches
5) Pericardial branches
6) Mediastenal branches
7) Superior phrenic arteries
• Is the continuation of the
descending thoracic aorta at the
lower end of the 12th thoracic
vertebrae
• Branches:
1) Inferior phrenic arteries
2) Celiac artery
3) Superior mesenteric artery
4) Middle suprarenal artery
5) Renal artery
6) Gonadal artery
7) Lumbar arteries
8) Inferior mesenteric artery
9) Median sacral artery
10) Common iliac artery

26. AORTIC DISSECTION
Tear in the intima of the aorta
resulting in blood surging
through the tear, between the
intima and media of the aorta
Signs and symptoms:
• Sudden severe sharp pain in
the chest or upper back,
described tearing stabbing or
ripping pain
• Shortness of breath
• Fainting or dizziness
• Low BP
• Rapid weak pulse
• Heavy sweating
• Loss of vision & confusion

27. PULMONARY TRUNK
Carries deoxygenated
blood from the right
ventricle to the lungs
Divides into right and
left pulmonary arteries
The left pulmonary artery is
connected to the arch of aorta at
its inferior aspect via the
ligamentum arteriosus, remnant
of ductus arteriosus

28. LYMPHATICS OF HEART
• Lymphatics accompany coronary
arteries and have two trunks
• Right trunk ends in
brachiocephalic nodes
• Left one ends in tracheobronchial
nodes

29. VALVES
• Valves ensure unidirectional flow of blood
Heart valves
Atrioventricular
valve
Tricuspid valve
Mitral valve
(4-6sqcm)
Semilunar
valve Pulmonary
valve
Aortic valve
(3-4 sqcm)

30. Produces 2nd
heart sound
Produces 1st
heart sound
Produces 2nd
heart sound
Produces 1st
heart sound

31. PULMONARY AND SYSTEMIC CIRCUATION

32. INNERVATION OF THE HEART
SYMPATHETIC INNERVATION:
• Derived from upper 4 to 5
thoracic segments of spinal cord
• They are cardio-acceleratory,
hence upon stimulation they
increase heart rate
• Also dilate coronary arteries
PARASYMPATHETIC
INNERVATION:
• Reaches heart via Vagus
nerve
• Cardio-inhibitory, hence
reduces heart rate upon
stimulation
Both parasympathetic and
sympathetic nerves form the
superficial and deep cardiac
plexus, branches of which run
along the coronary arteries to
reach the myocardium

33. Both parasympathetic and
sympathetic nerves form the
superficial and deep cardiac
plexus, branches of which run
along the coronary arteries to
reach the myocardium
SUPERFICIAL CARDIAC PELXUS
• Situated below the arch of aorta below
the right pulmonary artery
• Formed by:
a) Superior cervical cardiac branch of
the left sympathetic chain
b) Inferior cervical cardiac branch of
the left vagus nerve
DEEP CARDIAC PLEXUS
• Situated in front of the bifurcation of
trachea, behind the arch of aorta
• Formed by all the cardiac branches
derived from all the cervical and upper
thoracic ganglia of the sympathetic
chain, and the cardiac branches of
Vagus nerve, and the recurrent
laryngeal nerve (except those which
form the superficial plexus)

34. CONDUCTING SYSTEM
• Made up of myocardium that is
specialised for initiation &
conduction of the cardiac impulse
• Consists of
1. SA node
2. AV node
3. Right &Left bundle branches
4. Purkinje Fibres

35. CONDUCTING SYSTEM
SA Node:
• Also known as the
“pacemaker” of the
heart
• Initiates the heart beat
• Situated at the
atriocaval junction
• Generates impulses at
the rate of 70 – 100
beats/min
• Impulse travels
through the atrial wall
to reach the AV node
AV Node:
• Smaller than the SA Node
• Situated at the dorsal and lower
part of the atrial septum, just
above the opening of the
coronary sinus
• Generates impulses at the rate of
40 – 60 beats /min
AV Bundle or The Bundle of
His:
• Begins from the AV Node
crosses AV ring & descends
along the posteroinferior
border of the membranous part
of the ventricular septum
• At the upper part of muscular
septum, divides into left and
right branches
Both right and left fibres divides into
Purkinje fibres
Purkinje Fibres:
• Subendocardial plexus
• Double nuclei
• Generates impulses at the rate
of 20 – 35 beats/ min

38. HEART BLOCKS
AV BUNDLE BLOCK
Block can occur at the AV node, bundle of His or bundle
branches
First degree
heart block:
• Increase in
vagal tone
• Digitalis
toxicity
• Inferior wall
MI
• Myocarditis
2nd degree
heart block
(type 1)
Wenckebach:
• Most
commonly
seen in post
inferior wall
MI with AV
node
ischemia
2nd Degree heart
block (type 2):
• Diseased
bundle of His
with BBB
3rd degree heart
block:
• Complete heart
block with atria
and ventricle
beating
independently
&atria beating
faster than
ventricles
Bundle Branch
Block:
1. RBBB: more
common and
associated with
ASD, IHD and
valvular heart
disease
2. LBBB

43. RBBB

44. LBBB

45. CORONARY CIRCULATATION
• Coronary artery disease (CAD) is one of the
leading causes of sudden death.
• Accounts for one third of all perioperative death.
• Knowledge is must for all.
• Tip of the iceberg

46. Anatomy of coronary arteries
Origin from Aortic Sinus
Right coronary artery 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..
Left coronary artery The left coronary artery (left
main coronary artery) emerges from the aorta through
the ostia of the left aortic cusp.
The left coronary artery travels from the aorta, and
passes between the pulmonary trunk and the left atrial
appendage.
Under the appendage, the artery divides into the
anterior interventricular (left anterior descending
artery) and the left circumflex artery

47. Origin of arteries

48. BLOOD SUPPLY OF THE HEART
CORONARY ARTERIES
• Arise from ascending
aorta.
• Two major arteries are
RCA &LCA
• These two branches
subdivide and course over
the surface of the heart
(epicardium) progress
inward to penetrate the
epicardium and supply
blood to the transmural
myocardium.

49. Left coronary artery and supply
Left anterior descending artery Left circumflex artery

50. Right coronary artery and supply
Right marginal artery Posterior desecending artey

51. Dominance

52. External aspect of coronary artery
Normal Arterial wall

53. Coronary artery disease development

55. ECG Changes in MI

59. Endocardial to epicardial relationship
During systole when heart
muscle contracts it compresses
the coronary arteries therefore
blood flow is less to the left
ventricle during systole and more
during diastole.
Blood flows to the
subendocardial portion of Left
ventricle ,which occurs only
during diastole.

60. Physiology of coronary circulation
• Normal coronary blood flow 0.6 to 0.8ml/gm/min.
• Coronary blood flow at rest is about 200-250 ml/min, which is about 5
percent of the cardiac output .
• During exercise coronary blood flow increase four time -1000ml/min.

61. Myocardial oxygen consumption
• Normal myocardial oxygen consumption in normal beating heart -
8ml/min/100gm.
• Myocardial oxygen consumption in heavy exercise – 70ml/min/100
gm.
• Myocardial oxygen consumption in arrested heart -2ml/min/100
gm.
• Myocardial oxygen extraction- 75%
REASON:
•As heart muscle has more mitochondria, up to 40% of cell is occupied by mitochondria, which can generate energy for
contraction by aerobic metabolism, heart needs more O2 as compared to other tissues.
•Hence when oxygen demand increases e.g. exercise, O2 supply can be increased to heart only by increasing blood flow.

62. Principle
• Adjusting the lumen.
• Adjusting the mean aortic pressure.
• Oxygen demand and supply.

63. Factor affecting coronary blood flow
1 Mechanical.
2 Metabolic and
Hormonal.
3 Neural.

64. Mechanical factor
• Phasic flow: Coronary perfusion is intermittent rather than continuous
• Autoregulation of blood flow: Coronary blood flow will be maintained
despite of changes in perfusion pressure. Myocardium will regulate its own
blood flow between a perfusion pressure of 40 to 140 mmHg beyond this it
will be pressure dependent
• Regional variation of blood flow: Regional coronary blood flow remains
constant as coronary artery pressure is reduced below aortic pressure over
a wide range when the determinant of myocardial oxygen consumption are
kept constant.
• The major determinants of myocardial oxygen consumption are heart rate,
systolic pressure and left ventricular contractility

65. PHASIC FLOW IN CORONARIES

66. Pressure In Different Chambers Of
Heart
 As in systole pressure in left ventricle is slightly higher than in
aorta , so the coronary blood flow reduces.
 On the other hand press diff in aorta & right ventricle & aorta &
right atrium is more during systole than diastole, coronary blood
flow is not appreciably reduce during systole

67. Autoregulation of coronary blood flow
• The ability of heart to
maintain flow constant in
the face of a change in
perfusion pressure
without the intervention
of any other external
mechanism.
• This increase from
baseline to maximum flow
has been termed as
coronary flow reserve
(CFR)

69. CORONARY VASCULAR RESISTANCE AND ITS
RELATION TO FLOW AND PRESSURE
• Coronary blood flow provides the needed oxygen supply for any given
myocardial oxygen demand and normally increases automatically from a
resting level to a maximum level in response to increase in myocardial
oxygen demand from exercise and neurohormonal or pharmacological
hyperemic stimuli.
• The resistance of coronary blood flow can be divided into three major
components: R1 (Epicardial vessels), R2 (Myocardial vessels), R3
(Subendocardial vessels)
• When coronary reserve is normal these 3 resistances are assumed to be
functioning normally

71. Influence of Metabolic Factor on coronary
circulation
Vasodilators
• Adenosine and its compounds.
• Ion K+, H+, Ca2+
• Carbon dioxide and oxygen.
• Prostaglandins
Vasoconstrictors
• ThromboxaneA2
• Endothelin
• Prostacyclin 1
• Bradykinin
• Angiotensin2

72. Neural Factors
• Sympathetic: Epicardial vessels contain alpha receptors
and causes vasoconstriction and endocardial vessels
contain beta receptors and cause vasodilation
• Parasympathetic : very little but vasodilation

73. VEINS OF THE HEART
1. Great cardiac vein
2. Middle cardiac vein
3. Right marginal vein
4. Posterior vein of the left
ventricle
5. Oblique vein of the left
atrium
6. Anterior cardiac veins
7. Venae cordis minimi

74. Coronary Sinus:
• Largest vein of the heart
(3cm long)
• Situated in left posterior
coronary sulcus
• Opens into posterior wall of
right atrium
Tributaries of coronary sinus:
1. Great cardiac vein: opens into left
end of sinus
2. Middle cardiac vein: opens into
middle part of sinus
3. Small cardiac veins: opens into right
end of sinus. Right marginal vein
drains into small cardiac vein or may
directly open into the right atrium
4. Posterior end of left ventricle
5. Oblique vein of left atrium of marshal:
terminates at left end of sinus

75. THANK YOU