Cardiac anaesthesia Reference: 1. Grays anatomy 2. Kirklins -cardiovascular surgery

1. Anatomy of Heart
Moderator: Dr. Sandip Junghare
Presenter: Dr. Sonalika Tudimilla
Dr. D. Y. Patil Medical College, Hospital & Research centre

2. INTRODUCTION
• The heart is a hollow
fi
bromuscular organ with a three dimensional spiral organisation
of conical or pyramidal form with base, apex, and series of surfaces with borders.
• It occupies the middle mediastinum between the lungs and their pleural coverings
• An average adult heart is 12 cm from base to apex, 8–9 cm at its broadest
transverse diameter and 6 cm anteroposteriorly.
• Its weight varies from 280 to 340 g (average 300 g) in males and from 230 to 280 g
(average 250 g) in females.
• Cardiac weight is 0.45% of body weight in males and 0.40% in females.
• The di
ff
erence in weight of the heart between males and females appears after the
age of 12 years.

3. • Adult weight is achieved between the ages of 17 and 20 years.
• The heart reaches 50% of its adult dimensions at birth, 75% by 5 years and
90% by 12 years
• The heart rests on the diaphragm, near the midline of the thoracic cavity.
• Lies within the pericardium, behind the sternum, 2nd to 6th costal cartilages
and in front of 5th to 8th thoracic vertebrae.
• 1/3rd of it lies to the right and 2/3rd of it lies to the left of median plane.

4. RELATIONS OF HEART
• Superiorly – the aorta, superior vena cava, pulmonary artery & vein
• Inferiorly – the diaphragm
• Anteriorly – the ribs and intercostal muscles
• Posteriorly – the oesophagus, trachea, right and left bronchus, descending aorta,
inferior vena cava & thoracic vertebrae
• Laterally – the lungs
• The apex is formed by the tip of the left ventricle & is directed anteriorly, inferiorly
and to the left. It is in the left 5th intercostal space, 9cm lateral to midsternal line.
• The base of the heart is its posterior surface. It is formed by both the atriums.

5. SURFACES OF THE HEART
The heart is described as having a base and apex; its surfaces are designated as sternocostal (anterior),
diaphragmatic (inferior), and right and left (pulmonary)
• STERNOCOSTAL OR ANTERIOR SURFACE: Deep to the Sternum & Ribs
• Separated by pericardium from the body of the sternum, sternocostal muscles & the 3rd to 6th coastal
cartilages.
• DIAPHRAGMATIC OR INFERIOR (HORIZONTAL) SURFACE: part of the heart between apex & right border
• slopes anterioinferiorly towards the apex & formed by ventricles and rests on central tendon but also apically
- left muscular part of diaphragm
• PULMONARY OR LEFT SURFACE: occupies Cardiac notch of the lung
• Faces posterosuperiorly to the left, consists almost entirely of the obtuse margin of left ventricle, part of left
atrium & its appendage
• Convex/ widest superiorly, & is separated by the pericardium from the left phrenic neurovascular bundle, and
by the left pleura from the deep concavity of the left lung.
• RIGHT SURFACE: rounded / right atrial wall.

6. POSTEROINFERIOR VIEW
ANTERIOR VIEW

7. BORDERS OF THE HEART
• SUPERIOR OR UPPER BORDER: formed by both atria (mainly left) & is slightly
oblique.
• Anteriorly- Ascending aorta & Pulmonary trunk
• INFERIOR BORDER (ACUTE MARGIN): sharp, thin & horizontal is formed by
right ventricle and partly left ventricle
• RIGHT BORDER: formed by right atrium and it faces the right lung and extends
from the inferior surface to the base.
• LEFT BORDER OR PULMONARY BORDER (OBTUSE MARGIN): formed by
left ventricle and the left auricle and it faces the left lung and descends obliquely,
convex to the left, from the appendage to the cardiac apex.

8. • Although the heart is
placed obliquely in the
thorax, the atrial and
ventricular Septal
structures are virtually
in line, but inclined
forwards and to the
left at 45 degree to
the Sagittal plane

9. SULCI/GROOVES OF THE HEART
The division of the heart into four chambers produces boundaries that are visible externally as
grooves (sulci).
• INTERATRIAL GROOVE OF WATERSON
• ATRIOVENTRICULAR SULCUS (CORONARY SULCUS): Separates atria from
ventricles, & contains main trunks of the coronary arteries, circum
fl
ex artery, coronary
sinus.
• ANTERIOR INTERVENTRICULAR SULCUS: lies between left ventricle and right
ventricle on the the anterior surface, marks location of interventricular septum &
contains left anterior descending artery, great cardiac vein.
• INFERIOR/ POSTERIOR OR DIAPHRAGMATIC SULCUS: lies between left ventricle
and right ventricle posterior surface, & contains posterior interventricular artery and
middle cardiac vein.

10. PERICARDIAL SINUSES
• The lines of reflection between visceral and parietal pericardium form two pericardial
sinuses.
a. The transverse pericardial sinus lies anterior to the superior vena cava and
posterior to the ascending aorta and pulmonary trunk.
b. The oblique pericardial sinus lies posterior to the heart to the pericardial sac.

11. COVERINGS OF THE HEART
• Pericardium:
• The heart is enclosed in double-walled sac called the pericardium.
• It consist of two main parts: 1. The
fi
brous pericardium.
2. The serous pericardium
• The
fi
brous pericardium is composed of tough, non elastic, dense irregular
connective tissue. The functions of
fi
brous pericardium is to
1. Prevent overstretching of the heart
2. Protection of heart
3. Anchors the heart in the mediastinum

12. • The serous pericardium is a thinner membrane that forms a double layer
around the heart.
• Outer parietal layer: is fused to the
fi
brous pericardium.
• Inner visceral layer is also called the epicardium helps the layers of the heart
wall to adheres tightly to the surface of the heart.
• A slipper
fl
uid is present in between the parietal and visceral layers helps to
give lubrication and reduces friction while the heart beats in the pericardial
fl
uid.
• The space between the two layers is called the pericardial cavity.

13. LAYERS OF THE HEART
• The wall of heart consists of three layers:
• The epicardium (external layer)
• The myocardium (middle layer)
• The endocardium (inner layer)

14. Epicardium
• It is thin transparent outer layer of heart wall.
• Composed of mesothelium.
• Contains blood vessels, lymphatics and
vessels that supply myocardium.
Myocardium
• Is responsible for the pumping action of the
heart.
• Composed of cardiac muscle tissue.
• Cardiac muscle
fi
bers are organized in
bundles that swirl diagonally around the
heart and generate pumping actions of heart.
Endocardium:
• Is a glistening white sheet of endothelium.
• Lines the heart chambers.
• Covers the
fi
brous skeleton of the valves.
• Is continuous with the endothelial linings
of the blood vessels leaving and entering
the heart.

16. CHAMBERS OF SECRETS
The heart has four chambers.
• The two superior receiving
chambers are the atria and
• The two inferior pumping
chambers are the ventricles.

17. RIGHT ATRIUM
General & External features
• Anterior & to the right of left atrium,
forms right border
• The junction between the venous part
(sinus venosus) and the atrium proper
is marked externally by a shallow
groove, the sulcus terminalis
• Extends between the right sides of the
openings of the two venae cavae.
• The sulcus terminalis corresponds,
internally, to the terminal crest (crista
terminalis), which is the site of origin
of the extensive pectinate muscles.

18. • Anteriorly, is related to the anterior part of the mediastinal surface of the right lung,
from which it is separated by pleura and pericardium.
• Posteriorly, the vertical interatrial groove descends to the crux.
• Posteriorly and to the left, the interatrial septum and the surrounding infolded atrial
walls separate the atria (the mural infolding is indicated by an extensive interatrial
groove).
• Posteriorly and to the right are the right pulmonary veins
• Laterally, is also related to the mediastinal surface of the right lung, but anterior to its
hilum and separated from it by the pleura, right phrenic nerve and pericardiophrenic
vessels and pericardium.
• Medially are the ascending aorta and, to a limited extent, the pulmonary trunk and its
bifurcation.

19. Internal features
• Receives blood from three veins: Superior Vena Cava, Inferior Vena Cava and Coronary sinus.
• Thickness: 2-3mm
• Anterior wall: rough due to presence of muscular ridges called pectinate muscles.
• Posterior wall: smooth
• Three regions:
Smooth walled venous component: located posteriorly leads Anteriorly to the vestibule of tricuspid valve
Receives opening of vena cavae & coronary sinus
Eustachian valve:
fl
ap like, fold of endocardium, anterior to IVC ori
fi
ce (laterally or right margin) - eustachian ridge -continuous with valve
of coronary sinus
Thebesian valve: at ori
fi
ce of coronary sinus
• Coronary sinus: starts at the con
fl
uence of the oblique vein of the left atrium and the great cardiac vein, and receives the middle
and small cardiac veins close to its junction with the right atrium
• Fossa ovalis: Is an oval depression & a prominent feature of interatrial septum
• Crista Terminalis: a smooth, C-shaped muscular ridge, separates right atrium & its appendage from venous sinus and also
Trabeculated from Non trabeculated part (Venous part)
• Tricuspid valve

20. • TRIANGLE OF KOCH is de
fi
ned between the
attachment of the septal lea
fl
et of the tricuspid valve,
the anteromedial margin of the ostium of the
coronary sinus, and the palpable round, collagenous
subendocardial Tendon of Todaro
• Koch’s triangle is a landmark of particular surgical
importance, indicating the site of the
atrioventricular node and its atrial connections.

21. • Sino atrial node - superior part of the
groove, inferolateral to the ori
fi
ce of SVC
• Pectinate muscles- extend anterolaterally
from the terminal crest, reaching into the
appendage where they form several
trabeculations
• Largest- taenia sagittalis (second crest or
septum spurium).
• Torus aorticus- bulging atrial wall
anterosuperior to the membranous septum
& marks the location of non coronary aortic
sinus

22. RIGHT AURICLE
• An extensive muscular pouch, the appendage, projects anteriorly to overlap
the right side of the ascending aorta.
• Broad, triangular, pyramidal structure and has a wide junction with the venous
component of the atrium
• Wide based, blunt ended

23. RIGHT VENTRICLE
General & External features
• Crescentric
• Convex anterosuperior surface of the right
ventricle forms the sternocostal surface of heart
• Inferior surface-
fl
at, & related to central tendon
• Wall thickness: 3- 5 mm
• Ratio of the thickness of the two ventricular
walls, RV : LV = 1:3
• Interventricular septum -forms left & posterior
wall

24. Internal features
• Right Ventricle extends from the right
atrioventricular (tricuspid) ori
fi
ce nearly to the
cardiac apex —>ascends to the left —>
infundibulum or conus arteriosus —> pulmonary
ori
fi
ce
• Supraventricular crest (Crista
supraventricularis) - separates inlet & outlet
components in the roof of the ventricle, it thick,
muscular, & highly arched structure
• Inlet: trabeculated, Outlet or Infundibulum:
smooth walls
• Trabeculated appearance - myriad of endocardial,
lined, irregular muscular ridges and protrusions
collectively known as trabeculae carneae
• Papillary muscles —> chordae tendinae inserted
into free edge of Atrioventricular valves
• Septal band, towards the Apex- supports anterior
papillary muscle of Tricuspid valve crosses
parietal wall of ventricle as moderator band

25. • Septal surface: inlet portion, a
trabeculated portion & outlet portion
• Alternatively, may be divided into
Posterior (Basal), Middle, Apical
(Anterior) & Infundibular (conal)
portions.
• Second part of the outlet portion of
the septum is the anterior (superior)
extension of the trabecula
septomarginalis (septal band).
• Parietal extension of the
infundibular septum: IS merges with
the free right ventricular wall
• Parietal band: anterior to right aortic
sinus, and is termed
ventriculoinfundibular fold.
• Crista Superventricularis: parietal
band + infundibular septum

26. LEFT ATRIUM
Internal & External Features
• Roughly cuboidal, Smaller in volume than the right
• Posterior aspect (quadrangular) forms anatomical base of the heart, and forms anterior wall of the oblique
pericardial sinus
• Wall Thickness: 3mm
• Venous component: Right & Left Superior & Inferior pulmonary veins
• Pulmonary veins open into the superior posterolateral surfaces of the left atrium, two on each side
• Myocardial Sleeve: initiates atrial
fi
brillation
• Vestibule: smooth circumferential area of atrial wall that surrounds the ori
fi
ce of the mitral valve
• Appendage
• No Crista terminalis

27. LEFT AURICLE
• Longer, narrower and more hooked than
the right, is a
fi
nger-like extension with
more deeply indented margins.
• Pectinate muscles are smaller than the
right
• Tip: lies variably over pulmonary trunk &
anterior interventricular artery, it’s narrow
morphology renders it a potential site for
deposition of Thrombi
• Mitral or left atrial isthmus

28. LEFT VENTRICLE
General & External Features
• Powerful pump for the high-pressured systemic arterial circulation which forms
the apex of the heart
• Half ellipsoid or cone shaped, longer & narrower than RV
• Wall Thickness: 8-12 mm (three times thicker than the RV)
• Forms a Part of Sternocostal, Left and Inferior cardiac surfaces
• Shape of the left ventricle changes from elliptical in the neonatal period to the
round adult shape later in infancy
• The e
ff
ect of obesity on the heart is apparent as early as the second year of life.

29. Internal Features
• Inlet: guarded by Mitral valve (Ostium Venosum),
• Outlet: guarded by Aortic valve (Ostium Arteriosum)
• Apical Trabecular component
• Subaortic Curtain: ori
fi
ces within the left ventricle are in close contact with
fi
brous continuity between the lea
fl
ets of the aortic and mitral valves
• Trabeculae carneae & chordae tendineae that anchor the cusps of the
bicuspid valve to papillary muscles.

31. COMPARISON OF RIGHT & LEFT ATRIUM
COMPARISON OF RIGHT & LEFT VENTRICLE
RIGHT ATRIUM LEFT ATRIUM
Receives venous blood from body Receives oxygenated blood from lung
Pushes blood to right ventricle through tricuspid valve Pushes blood to left ventricle through bicuspid valve
Forms right border, parts of sternocostal and small part of
base of the heart
Forms major part of the heart base
RIGHT VENTRICLE LEFT VENTRICLE
Thin, crescentric Thick, circular
Pushes blood only to the lung Pushes blood to entire body except lung
Contains three papillary muscles Contains two papillary muscles
Forms sternocostal surface Forms diaphragmatic surface

33. VALVES OF THE HEART

34. ATRIOVENTRICULAR VALVES
Tricuspid valve
• Ori
fi
ce (associated annulus), the Lea
fl
ets, the supporting Chordae Tendinae & Papillary muscles
• ORIFICE: triangular, 11.4 cm in males, 10.8 cm in females, is vertical but 45° to the sagittal plane.
• LEAFLETS: reduplication of endocardium enclosing a collagenous core, three lea
fl
ets are
distinguished based on the Zone of apposition between them.
• Anterosuperior- largest, attached on posterolateral aspect of supraventricular crest
• Septal - border of triangle of Koch
• Inferior (posterior)
• Base of cusps attach to the
fi
brous ring of the heart skeleton and their free edges attach to the
chordae tendineae connecting them to the papillary muscles.
• CHORDAE TENDINEAE: Fibrous collagenous structures that supports the lea
fl
ets of AV valves
• false chordae connect the papillary muscles to each other or to the ventricular wall or septum,
• 40% of these false cords contain conduction cardiomyocytes.

35. • True chordae; arise from small projections on tips of margins of apical third of papillary muscles
• First, second & third order types, according to the distance of the attachment from margins of lea
fl
ets
• Fan shaped, rough, free edge, deep, basal
• PAPILLARY MUSCLES: Anterior (Largest) - arises from right anterolateral ventricular wall &
• Inferior (bifold or tri
ffi
d) - arises from myocardium inferior to the inferoseptal commissure, smaller- medially septal muscle of
conus, the muscle of Lancisi
• Feature of the right ventricle is that the septal lea
fl
et is tethered by individual chordae tendineae directly to the ventricular
septum; such septal insertions are never seen in the left ventricle.
TRICUSPID VALVE VIEWED FROM RIGHT ATRIUM

36. MITRAL VALVE
• Ori
fi
ce with a supporting annulus,
lea
fl
ets and a variety of chordae
tendinaeae and papillary muscles
• Ori
fi
ce: 9.0 cm in males 7.2 cm in
females
• Circular ori
fi
ce: vertical and at 45
degree to the sagittal plane in diastole
• When the mitral valve lea
fl
ets close,
they form a single zone of coaptation,
termed the commissure.
• Annulus -
fi
brocollagenous elements,
increases linearly with BSA in children
and young adults
• Lea
fl
ets- Bicuspid, smaller and
thicker than Tricuspid valve

37. • Anteromedial (Inferoseptal) lea
fl
et:
larger & intervenes between the
atrioventricular and aortic ori
fi
ces
• Posteroseptal (Superoposterior) lea
fl
et
• Chordae Tendineae: four types-
interlea
fl
et (commissural), rough zone
( including the special strut chordae),
‘cleft’ and basal chordae.
• True mitral valve chordae: Interlea
fl
et
(commisural), rough zone (including the
special strut chordae), cleft and basal
chordae
• Papillary muscles: Anterolateral
(Superolateral) arises from the
sternocostal mural myocardium,
• Posteromedial (inferoseptal) from the
diaphragmatic region
• Blood vessels are present in the
fi
brous
ring & basal 1/3rd of the lea
fl
et

38. SEMILUNAR VALVES
PULMONARY VALVE
• Guards the out
fl
ow from the RV
• Faces superiorly to the left and slightly posteriorly.
• Ori
fi
ce- obliquely positioned
• Three semilunar lea
fl
ets: Anterior, right & left Lea
fl
ets
• Formed by folds of endocardium and some connective
tissue.
• The free margin of each lea
fl
et contains a central
localized collagenous thickening, the nodule of
Arantius.
• No annulus, chordae tendineae or papillary muscles
supporting the lea
fl
ets of the valve

39. AORTIC ROOT
• Anatomical bridge between the Left Ventricles & the
Ascending Aorta
• Consists of Aortic Valvular Lea
fl
ets (supported by
Aortic sinuses of Valsalva) & Inter-lea
fl
et triangles with
Aortic Sinuses
• Each sinus & its Lea
fl
et - Hemispherical Chamber
• Semilunar attachment of the lea
fl
ets- no proximal
border, limited distally by Sinotubular Junction
• Fibroelastic tissue & muscular portion (2/3rds of its
widest circumference
• Two rings within the root : doesn’t support valve
lea
fl
ets
• Two lea
fl
ets are supported by muscle, and the third has
an exclusively
fi
brous attachment.

40. Aortic Valve Lea
fl
ets
• Sinuses and lea
fl
ets are conveniently named as right, left and
non-coronary, according to the origins of the coronary
arteries
• Semilunar attachments incorporate three triangular areas
(trigones) of aortic wall within the apex of the left ventricular
out
fl
ow tract.
• First triangle: between the non-coronary and left coronary
lea
fl
ets, has a base continuous inferiorly with the
fi
brous
aortic–mitral curtain.
• Second triangle: between right and non-coronary lea
fl
ets,
has the membranous components of the inter- ventricular
septum as its base and thus ‘faces’ the right ventricle,
whereas its apex ‘points’ towards the transverse pericardial
space behind the origin of the right coronary artery.
• Third triangle, between the two coronary lea
fl
ets, has its
base on the muscular interventricular septum and its apex
‘points’ to the plane of space found between the aortic wall
and the free-standing sleeve of right ventricular infundibular
musculature that supports the lea
fl
ets of the pulmonary valve.
• Closed Valve: appears Triradiate

41. Aortic Sinuses of Valsalva
• Upper limit forms well de
fi
ned circumferential Sinutubular ridge on aortic inner surface just above aortic valvular
lea
fl
ets
• Coronary arteries open near the ridge