normal heart,fetal circulation

1. M.elKhatib

2.  Understand the normal anatomy of the heart.
 Understand the size, shape, location and
orientation of the heart.
 Understand and locate the cardiac valves.
 Understand the route of blood flow through the
heart and lungs.

4. • The heart size is usually referred to
as the size of the persons fist.
• The heart is located mid sternal
with approximately 2/3 of the heart
mass on the left side.(levocardia)
•The heart is a muscular, hollow cone
shaped organ.
• In a normal heart, the apex of the
heart faces to the left.
• There are conditions when the
heart does not face this way such as
dextrocardia,mezocardia

5.  The heart has four chambers that are divided into
2 areas.
 The first is the atria which has two chambers, the
right atrium (RA) and the left atrium (LA).
 The atriums are located on the top half of the
heart and are less muscular then the ventricles.
 They bring blood into the heart. The right side or
RA brings de-oxygenated blood into the heart and
the left side (LA) brings oxygenated blood back
into the heart.

6.  The second area is the ventricles which is split into the
Right Ventricle (RV) and the Left Ventricle (LV).
 The ventricles are located at the bottom of the heart.
 The ventricles are more muscular then the atriums
because they are the pumping chambers.
 The RV pumps the de-oxygenated blood to the lungs
to be oxygenated.
 The LV pumps the oxygenated blood to the body so
that they can oxygenate the organs and tissues.

7. There are two types of
valves in the heart;
Atrioventricular valves
and semilunar valves.
There are two
atrioventricular valves in
the heart. The first is the
tricuspid valve which is
located on the right side of
the heart.
It separate the right
atrium from the right
ventricle. This valve has
three leaflets
The second is the mitral
valve. Located on the left
side of the heart, it
separates the left atrium
from the left ventricle. The
mitral valve is bicuspid
and has two leaflets.

8. The Pulmonary Valve
(PV) is described as a
semilunar valve. It
separates the Right
Ventricle (RV) from the
Pulmonary Artery
(PA).

9. The Aortic Valve
(AoV) is also
described as a
semilunar valve. It
separates the Left
Ventricle (LV) from
the Aorta (Ao).

10. The heart is made of
three tissue layers:
• Endocardium
• Myocardium
• Pericardium

11.  The outer layer of the heart is called the Pericardium.
 The pericardium is a double layered sac. The outer sac
is made of fibrous tissue and adheres to the diaphragm
and coats the great vessels (pulmonary artery and
aorta) to ensure that they stay in the correct position
and to protect them.
 The inner layer is serous and secretes a substance
called pericardial fluid. This stops friction between the
layers of the heart.
 When the fluid builds up, it can cause pericarditis or
cardiac tamponade. If the fluid leaks, it can cause a
pericardial rub.

12.  The second layer is the Myocardium which is an
involuntary muscle and is branched in
appearance.
 The contraction of the heart and ejection of blood
to both the systemic and pulmonary circulations is
the myocardium's responsibility.
 Lastly is the Endocardium which is a single thin
layer of endothelium that lines the inside of the
myocardium.

13.  The blood from the body, or systemic blood
comes back to the heart via the Inferior Vena
Cava (IVC)
 The blood from the head returns to the heart via
the Superior Vena Cava (SVC)
 From the IVC and SVC, the blood which is de-oxygenated
or desaturated enters the right atrium
(RA).
 The right atrium also receives a flow of de-saturated
blood from the coronary sinus

14.  RA connects to the RV via the tricuspid valve
 RV is a pumping chamber and pumps blood through the
pulmonary valve, up the main pulmonary artery, divides to
the left and right pulmonary artery, to the respective left and
right lungs.
 In the lungs, the blood is re-oxygenated and returns to the
heart via the 4 pulmonary veins (PV)
 The 4 Pulmonary Veins connect to the Left Atrium (LA)
 The LA is connected to the Left Ventricle (LV) via the mitral
valve (Bi-leaflet)
 LV is also a pumping chamber and pumps the oxygenated
blood through the aortic valve, up the aorta and to the head
and body.

15.  The aorta has many important arteries that come
off it.
 The first is the coronary arteries which come off at
the base of the aorta and supplies the hearts
muscle with oxygenated blood.
 Further up the aorta just after the ascending aorta,
we come to the aortic arch. Off the aortic arch,
there are three main branches.

16. • The first main artery that
comes off the arch of the aorta
is the brachiocephalic artery
which is short and splits off to
the right subclavian and right
common carotid artery.
• The right subclavian artery
supplies the right arm while
the right common carotid
artery supplies the head.
• The second branch is the left
common carotid artery. This
artery also supplies the head
on the other side.
• Both common carotid
arteries branch further up to
become the external carotid
artery (ECA) and internal
carotid artery (ICA)
• The last in the left
subclavian artery which
supplies blood to the left arm.

19.  Atrial contraction
 Isovolumetric contraction
 Ejection
 Isovolumetric relaxation
 Passive filling

20. What is the difference?
Lungs are not used – high PVR, amniotic fluid
Placenta responsible for oxygenation, nutrition and
removal of waste
Use of foetal shunts
 Ductus Venosus
 Foramen Ovale
 Ductus arteriosus

22.  Oxygenated blood from placenta via umbilical vein
 Separates at liver
 Connects to IVC via ductus venosus
 Liver has high o2 demand – mixture of
de/oxygenated blood
 Foetal haemoglobin has a high affinity for o2
 High cardiac output

23.  Blood flows from IVC to RA
 Eustachian valve/crista dividens direct blood
toward foramen ovale
 Intra atrial communication
 One way
 Right to left shunting across PFO

24.  Communication between PA and Ao
 Deoxygenated blood from SVC flows RA>RV>PA
 High PVR
 Blood follows path of least resistance
 Blood passes into descending aorta via the ductus
arteriosus

25.  2/3 of LV output perfuses upper limbs and brain
 Remaining 3rd mixes with blood from ductus
arteriosus and perfuses lower body
 Lower body saturations approx 55%
 Foetal haemoglobin has a high affinity for o2
 High cardiac output

27.  First breath!!
 Lungs and alveoli expand
 Rapid fall in pulmonary vascular resistance
 Amniotic fluid moves into interstital space and
absorbed by pulmonary capillaries and lymphatic
system

28.  Increased pulmonary venous return
 Increase in left atrial pressure
 Higher than RAP leads to functional closure of FO
 Umbilical cord tied and cut/clamped
 Arteries and veins constrict
 Become fibrous
 DA becomes ligamentum venosum

29.  Increase in o2 concentration
 Decrease in prostaglandin levels
 Constriction of smooth muscle
 Ductus arteriosus begins to close with 12-24
hours

30.  Some patients born with CHD will have a
condition that is incompatible with life
 Death will occur if no intervention
 Life is made possible by partially maintaining the
foetal circulation
 ‘Duct-dependent’

31.  Require patency of the ductus arteriosus for
mixing of blood or maintaining blood flow
 Typical conditions include coarctation of the aorta
(CoA), transposition of the great arteries (TGA)
and hypoplastic left heart syndrome (HLHS)
 Duct patency maintained via IV prostaglandin
infusion @ 5-20ng/kg/min until palliative or
corrective interventions available

32.  The normal anatomy of the heart.
 The size, shape, location and orientation of the
heart.
 The cardiac valves.
 The route of blood flow through the heart and
lungs.