Transcript Clinical Anatomy of Pericardium and Heart part 1

Clinical Anatomy
Of Pericardium and Heart
Lecture 1 out 2
Associate Professor
Dr. Alexey Podcheko
Upd. Fall 2014
Intended Learning Outcomes
A. Pericardium:

To know the organs of the middle mediastinum,
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To know parts of the pericardium, innervation and blood supply
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Surgical aspects of pericardial anatomy

Clinical insights on pericardium
B. Heart:

To know the external features of the heart.

To know the chambers, valves, vessels, and related structures of
the heart including the pathway of blood flow.

Describe the mechanism of the heart sounds formation.

To know the layers of the heart wall (epicardium, myocardium,
and endocardium).

To know the course and distribution of the coronary arteries and cardiac veins.

To know coronary dominance in regard to the posterior interventricular artery
(posterior descending artery; PDA).

To know the cardiac plexus and its contribution to heart innervation on
cardiac myocardium, cardiac cycle, and coronary arteries.

Outline the conducting system of the heart, including the location and function
of the SA node, AV node, AV bundle, and Purkinje fibers of the heart

Clinical insights on heart pathology
Concept of the Middle Mediastinum
•The mediastinum is the compartment of the thorax that occupies the space between
the 2 lungs and their surrounding pleural sacs.
Has 6 boundaries (Inferior, Superior, Right/Left Lateral boundaries, Anterior
boundary, Posterior boundary)
•Divided into two regions:
I. Superior mediastinum (above the heart and pericardial sac on the level of T4T5 intervertebral disc – brown dashed line, see below)
II. Inferior mediastinum further divided into 3 subdivisions: 1. Anterior mediastinum
2. Middle mediastinum 3. Posterior mediastinum
Structures of the Middle Mediastinum
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I. Pericardium (3 parts):
Visceral pericardium
Parietal pericardium (Fibrinous)
Pericardial cavity - space between the visceral and parietal pericardial layers

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Phrenic nerves. Descend from the neck to the diaphragm in the fibrous
pericardium.Clinical Insights
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II. Oblique cardiac sinus. The posterior space within the serous pericardium between
the visceral pericardium andparietal pericardium. It is limited superiorly and on the right
by the reflection between the visceral and parietal peritoneum between the arteries and
veins (superiorly) and the superior and inferior vena cava (right lateral side), but is
continuous with the the rest of the pericardial cavity to the sides and below.
III. Transverse pericardial sinus. Passageway that traverses the top of
the heart between the parietal pericardiumcovering the arterial plane and the parietal
pericardium covering the venous plane. This sinus arises as the heart folds and draws
the venous end toward the arterial end during embryonic development.
Diaphragmatic Paralysis
Pericardiacophrenic artery and pericardiacophrenic vein. Pass with the phrenic
nerve to supply the diaphragm.
Heart. The muscular pump of the cardiovascular system that
pumps blood throughout the blood vessels of the pulmonary and systemic circuits.
PERICARDIUM
 Is a fibroserous sac that encloses
the heart and the roots of the great
vessels and occupies the middle
mediastinum.
 Is
composed
of
the
fibrous
pericardium and serous pericardium.
 Receives
blood
from
pericardiophrenic,
bronchial,
esophageal arteries.
 Is
the
and
innervated by vasomotor and
sensory fibers from the phrenic and
vagus nerves and the sympathetic
trunks.
5
PERICARDIUM: 2 layers
•The pericardium is a closed sac
composed of two layers: Fibrous and
Serous
•The tough external layer, the fibrous
pericardium, is continuous with (blends
with) the central tendon of the diaphragm
PERICARDIUM: Serous layer has 2 portions
•The internal surface of the fibrous
pericardium is lined with a glistening
serous membrane, the parietal layer of
serous pericardium.
•This layer is reflected onto the
heart at the great vessels - aorta,
pulmonary trunk and veins, and
superior and inferior venae cavae as the visceral layer of serous
pericardium.
•The serous pericardium is
composed mainly of mesothelium, a single layer of flattened
cells forming an epithelium that
lines both the internal surface
of the fibrous pericardium
and the external surface of the
heart.
PERICARDIUM: Fibrous pericardium
•The fibrous pericardium is
continuous superiorly with the tunica
adventitia of the great vessels entering
and leaving the heart and fusing with the
pretracheal layer of deep cervical fascia.
PERICARDIUM: Fibrous pericardium
•The inferior wall (floor) of the
fibrous pericardial sac is firmly
attached and confluent (partially
blended) centrally with the central
tendon of the diaphragm.
•The site of continuity has been
referred to as the
pericardiacophrenic ligament;
however, the fibrous pericardium and
central tendon are not two separate
structures that fused together
secondarily,
nor are they separable
.
by dissection.
•As a result of the attachments just
described, the heart is relatively well
fixed in place inside this fibrous sac
PERICARDIUM: Fibrous pericardium
•The pericardium is influenced
by movements of the heart
and great vessels, the
sternum, and diaphragm
•The fibrous pericardium
protects the heart against
sudden overfilling because
it is so unyielding and
closely related to the great
vessels that pierce it
superiorly
•The ascending aorta
carries the pericardium
superiorly beyond the
heart to the level of the
sternal angle
PERICARDIAL CAVITY
•The pericardial cavity is
the potential space
between opposing layers
of the parietal and
visceral layers of serous
pericardium.
•It normally contains a
thin film of fluid that
enables the heart to move
and beat in a frictionless
environment.
•The visceral layer of
serous pericardium
makes up the epicardium,
the outermost of three
layers of the heart wall: (epicardium, myocardium and endocardium)
Epicardium and Pericardial Sinuses
•Extends onto the beginning of
the great vessels, becoming
continuous with the parietal
layer of serous pericardium,
where the aorta and pulmonary
trunk leave the heart and
where the superior vena cava,
inferior vena cava, and
pulmonary veins enter the
heart.
•The transverse pericardial
sinus lies between
Aorta+Pulmonary Trunk and
SVC+RPV/LPV
•the reflection of the serous
pericardium around the
RPV+LPV and IVC defines the
oblique pericardial sinus
Surgical Significance of the Transverse Pericardial Sinus
•The transverse
pericardial sinus
is especially
important to
cardiac surgeons.
•After the
pericardial sac is
opened anteriorly,
a finger can be
passed through
the transverse
pericardial sinus
posterior to the
aorta and
pulmonary trunk.
grafting.
•By passing a surgical clamp or placing a ligature
around these vessels, inserting the tubes of a
coronary bypass machine, and then tightening the
ligature, surgeons can stop or divert the circulation of
blood in these large arteries while performing cardiac
surgery, such as coronary artery bypass
The aortic cannula is seen at the most cephalad aspect of the field. Cardiopulmonary
bypass is initiated through a straight venous cannula placed within the right atrial
appendage
Blood Supply of the Pericardium
The arterial supply: mainly from
pericardiacophrenic artery - branch
of the internal thoracic artery (ITA),
parallels the phrenic nerve to the
diaphragm
Smaller contributions of blood come
from the:
1.Musculophrenic (branch of ITA)
2. Bronchial, Esophageal and
Superior phrenic arteries - branches
of the
.. thoracic aorta
3. Coronary arteries (visceral layer
of serous pericardium only), the first
branches of the aorta
The venous drainage:
Pericardiacophrenic veins,
tributaries of the brachiocephalic (or
internal thoracic)
veins + azygos venous system.
Nerve supply of the pericardium
1. Phrenic nerves (C3 C5), primary source of
sensory fibers; pain
sensations conveyed by
these nerves are commonly
referred to the skin (C3 - C5
dermatomes) of the
ipsilateral supraclavicular
region (top of the shoulder
of the same side).
2. Vagus nerves, function
uncertain.
3. Sympathetic trunks,
vasomotor
Exposure of the inferior vena cava and superior
vena cava
•After passing through the
diaphragm, the entire thoracic
part of the inferior vena cava
(approximately 2 cm) is
enclosed by the pericardium.
•Consequently, the pericardial
sac
. must be opened to expose
the superior part of the inferior
vena cava
•The same is true for the
terminal part of the superior
vena cava, which is partly
inside and partly outside the
pericardial sac.
Clinical Correlations: Pericarditis, and Pericardial
Rub
•Inflammation of the pericardium (pericarditis) usually
causes chest pain
•The pain is sharp in quality and increases with inspiration.
It radiates to the trapezius ridge and is partially relieved by
sitting up
•Pericarditis may also make the serous pericardium rough.
Usually the smooth opposing layers of serous pericardium
make no detectable sound during auscultation, but in
pericarditis friction of the roughened surfaces sounds like
the rustle of silk when listening with a stethoscope over the
left sternal border and upper ribs (pericardial friction rub)
•Heart sounds are understandably distant or muffled
• A chronically inflamed and thickened pericardium may
actually calcify, seriously hampering cardiac efficiency.
Some Types of Pericarditis
 Adhesive pericarditis with formation of plaquelike
fibrous thickenings
 Adhesive mediastinopericarditis is result of infectious
pericarditis, previous cardiac surgery, or irradiation to
the mediastinum
 Constrictive pericarditis - scar that limits diastolic
expansion and cardiac output, features that mimic a
restrictive cardiomyopathy. Cardiac output is reduced
at rest and heart has little if any capacity to increase
its output in response to increased peripheral needs
 Fibrinous pericarditis – due to accumulation of fibrin
Chronic
Constrictive
Idiopathic
Pericarditis
Encircling all of the heart by
massive pericardial calcific
deposits
Fibrinous pericarditis
Acute suppurative pericarditis arising
from direct extension of a pneumonia.
Extensive purulent exudate is evident.
A 34-year-old Caucasian female who is being evaluated for
proteinuria and a facial rash complains of chest pain. The
pain is sharp in quality and increases with inspiration. It
radiates to the trapezius ridge and is partially relieved by
sitting up. Which of the following is the most likely cause
of this patient’s chest pain?
A. Intimal hyperplasia of pulmonary arteries
B. Aortic dissection
C. Pericardial inflammation
D. Non-infectious cardiac valve vegetations
E. Cardiac tamponade
Clinical Correlations: Pericardial Effusion
Normal CXR
Pericardial Effusion
•Some inflammatory diseases produce pericardial effusion (passage
of fluid from pericardial capillaries into the pericardial cavity, or an
accumulation of pus).
•As a result, the heart becomes compressed (unable to expand and fill
fully) and ineffective.
•Non-inflammatory pericardial effusions often occur with congestive
heart failure
Clinical Correlations: Cardiac Tamponade
•The fibrous pericardium is a tough,
inelastic, closed sac that contains
the heart + thin lubricating layer of
pericardial fluid
•If extensive pericardial effusion
exists, the compromised volume
of the sac does not allow full
expansion of the heart, limiting the
amount of blood the heart can
receive, which in turn reduces
cardiac output.
•This phenomenon, cardiac
tamponade (a.k.a. heart
compression), is a potentially lethal
condition because heart volume is
increasingly compromised!!!!
Clinical Correlations: Hemopericardium
•Hemopericardium is the presence of
the blood in the pericardial cavity,
•Also produces cardiac tamponade
•Causes: a. perforation of a
weakened area of heart muscle
owing to a previous myocardial
infarction (MI) or heart attack,
•b. bleeding into the pericardial
cavity after cardiac operations
•c. from stab/gunshot wounds
•This situation is especially lethal
because of the high pressure
involved and the rapidity with which
the fluid accumulates.
•The heart is increasingly
compressed and circulation fails.
Clinical Correlations: Hemopericardium
 Clinical signs:
1. The veins of the face and neck
become engorged because of the
backup of blood
2. Another sign of the tamponade is
phenomenon of the “PULSUS
PARADOXUS” - paradoxic
pulse or paradoxical pulse, is an
abnormally large decrease in
systolic blood pressure and pulse
wave amplitude during inspiration.
The normal fall in pressure is less
than 10 mmHg during inspiration.
When the drop is more than 10mm
Hg, it is referred to as pulsus
paradoxus.
Clinical Correlations: Pneumopericardium
In patients with pneumothorax - ‘air or gas in the
pleural cavity’, the air may dissect along connective
tissue planes and enter the pericardial sac, producing
a pneumopericardium, which can be demonstrated
radiographically.
air or gas in
the pleural
cavity
Clinical Correlations: Pericardiocentesis
•Drainage of fluid from the pericardial cavity, pericardiocentesis, is usually
necessary to relieve cardiac tamponade.
•To remove the excess fluid, a wide-bore needle may be inserted through
the left 5th or 6th intercostal space near the sternum.
•This approach to the pericardial sac is possible because the cardiac notch in
the left lung and the shallower notch in the left pleural sac leaves part of the
pericardial sac exposed ‘the bare area’ of the pericardium.
Clinical Correlations: Pericardiocentesis
•The pericardial sac may also be
reached by entering the infrasternal
angle and passing the needle
superoposteriorly.
•the needle avoids the lung and
pleurae and enters the pericardial
cavity; however, care must be
taken not to puncture the internal
thoracic artery
•In acute cardiac tamponade from
hemopericardium, an emergency
thoracotomy may be performed
(the thorax is rapidly opened) so
that the pericardial sac may be
incised to immediately relieve the
tamponade and establish stasis of
the hemorrhage (stop the escape of
blood) from the heart.
End of Pericardium Part
ANATOMY of the HEART
The heart=a muscular double pump with 2 functions
Overview
 The right side receives oxygen-
poor blood from the body and
tissues and then pumps it to
the lungs to pick up oxygen and
dispel carbon dioxide
 Its left side receives
oxygenated blood returning
from the lungs and pumps this
blood throughout the body to
supply oxygen and nutrients to
the body tissues
Heart and Great Vessels: Part 1
•The heart, slightly larger
than a clenched fist, is a
double, self-adjusting,
suction and pressure pump,
the parts of which work in
harmony to propel blood to
all parts of the body.
•The right side of the heart
(right heart) receives poorly
oxygenated (venous) blood
from the body through the
superior vena cava and
inferior vena cava and
pumps it through the
pulmonary trunk to the
lungs for oxygenation.
Heart and Great Vessels
•The left side of the heart (left heart) receives well-oxygenated
(arterial) blood from the lungs through the pulmonary veins and
pumps it into the aorta for distribution to the body.
Heart simplified…
 Cone shaped muscle
 Four chambers
 Two atria, two ventricles
 Double pump – the ventricles
 Two circulations
 Systemic circuit: blood vessels that transport blood
to and from all the body tissues
 Pulmonary circuit: blood vessels that carry blood to
and from the lungs
Heart’s position in thorax
Heart Chambers
•The heart has four chambers: right and left atria and
right and left ventricles.
•The atria are receiving chambers that pump blood into
the ventricles (the discharging chambers).
Heart Valves
Valves: three tricuspid one bicuspid (cusp means flap)
 “Tricuspid” valve
 RA to RV
 Pulmonary or pulmonic
valve
 RV to pulmonary trunk
(branches R and L)
 Mitral valve (the
bicuspid one)
 LA to LV
 Aortic valve
 LV to aorta
Cardiac Cycle
•The synchronous pumping actions of the heart's two
atrioventricular (AV) pumps (right and left chambers)
constitute the cardiac cycle.
•For more details :
https://www.youtube.com/watch?v=ABTvNR59K5Q
Cardiac Cycle: Main Stages
•The cycle begins with a period of ventricular elongation
and filling (diastole) and ends with a period of ventricular
shortening and emptying (systole).
•Two heart sounds are heard with a stethoscope: a “lub”
sound as the blood is transferred (sucked) from the atria
into the ventricles and a “dub” sound as the ventricles
expel blood from the heart.
Cardiac Cycle: Heart Sounds
•The heart sounds are produced by the snapping shut of the oneway valves that normally keep blood from flowing backward
during contractions of the heart.
Cardiac Cycle: Heart Sounds
 Called S1 and S2
 S1 is the closing of AV (Mitral and Tricuspid) valves at
the start of ventricular systole
 S2 is the closing of the semilunar (Aortic and Pulmonic)
valves at the end of ventricular systole
 Separation easy to hear on inspiration therefore S2
referred to as A2 and P2
 Murmurs: the sound of flow
 Can be normal
 Can be abnormal
Cardiac Cycle: Heartbeat
Definition: a single sequence of atrial contraction followed
by ventricular contraction
 Systole: contraction
 Diastole: filling
 Normal rate: 60-100
 Slow: bradycardia
 Fast: tachycardia
***Note: blood goes to RA, then RV, then lungs, then LA, then LV, then
body; but the fact that a given drop of blood passes through the heart
chambers sequentially does not mean that the four chambers contract in
that order; the 2 atria always contract together, followed by the
simultaneous contraction of the 2 ventricles
Heart Wall Layers
•The wall of each heart chamber consists of three layers:
•Endocardium, a thin internal layer (endothelium and subendothelial
connective tissue) or lining membrane of the heart that also covers its
valves.
•Myocardium,
a thick, helical middle layer composed of cardiac muscle.
.
•Epicardium, a thin external layer (mesothelium) formed by the visceral
layer of serous pericardium
Heart Wall Layers
The walls of the heart consist mostly of thick myocardium, especially in the ventricles.
•Thickness of left ventricle myocardium is app. 10-15mm
•Thickness of right ventricle myocardium is app. 3-5mm
Heart Skeleton
The muscle fibers of the
myocardium are
anchored to the fibrous
skeleton of the heart.
Heart Skeleton is a
complex framework of
dense collagen forming
a. four fibrous rings that
surround the orifices of
the valves
b. right and left fibrous
trigone (formed by
connections between
rings)
c. membranous parts of the
interatrial and
interventricular septa
Heart Skeleton Functions
The fibrous skeleton of the
heart:
a. Keeps the orifices of the
atrioventricular (AV) and
semilunar valves patent
and prevents them from
being overly distended
b. Provides attachments for
the leaflets and cusps of
the valves.
c. Provides attachment for
the myocardium,
d. Forms an electrical
‘insulator’ so that atria and
ventricles may contract
independently