© Dr Jessica Middleton 2009
Heart
Anatomy
The heart consists of 4 chambers, the right and left atria and the right and left ventricles.
The right and left side of the heart can be thought of as two separate pumps with an
interventricular septum completely dividing them.
The right side of the heart is the pulmonary (lung) circulation getting the blood to the
lungs to oxygenate it and the left side of the heart circulates the oxygenated blood
round the body. The left side is a lot bigger (more muscular) than the right as it has a
much greater distance to pump the blood.
Circulation of the blood
The deoxygenated blood coming back from the body enters the right atrium from the
vena cava (main vein in the body) it then moves through to the right ventricle which
contracts, pumping the deoxygenated blood through the pulmonary artery to the
lungs to be oxygenated.
The oxygenated blood returns from the lungs to the heart through the pulmonary artery
into the left atrium, where it moves into the left ventricle which contracts and pumps
the blood into the aorta (major artery of the body) where it is then distributed round the
body.
Valves
The valves are the ‘one-way doors’ to keep the blood flowing the right direction
through the heart. They are made up of several flaps or cusps. There are 4 valves:
Tricuspid valve - between the right atrium and right ventricle
Pulmonary valve - at the exit of the right ventricle into the pulmonary artery
Mitral valve - between the left atrium and ventricle
Aortic valve - at the exit of the left ventricle into the aorta
The valves are held in place by filaments called chordae tendinae controlled by
papillary muscles.
Electrical System
The Heart beat is generated from the SA node or pacemaker of the heart, this is a
special area of tissue in the right atrium which generates its own nerve impulses which
spread down nerve fibres in the heart and trigger the muscle cells to contract. The
nerve impulses from the atria are conducted into the ventricles by an area of tissue
called the AV node, this acts as a fail-safe only letting through a certain number of
impulses to prevent the heart beating too fast.
These electrical impulses correlating with muscle contraction can be measured on an
ECG.
A 12 lead ECG looks at the heart from many different angles and can detect
abnormalities in the heart.
Coronary arteries
The blood supply to the heart itself is from the coronary arteries which come out of the
aorta. These vessels (Right and Left coronary artery) supply the heart with blood and
oxygen and are unfortunately particularly vulnerable to atherosclerosis.
© Dr Jessica Middleton 2009
Angina
As fatty deposits build up in the coronary artery walls and calcification and damage
occurs the diameter of the coronary vessels becomes less and less blood reaches the
heart tissue. This can show itself in the form of Angina as the heart muscle is not getting
as much oxygen as it needs and this gives pain.
Angina is chest pain that is likely from the heart and any chest pain that cannot be
explained needs to be further investigated with either an Exercise tolerance test (an
ECG whilst running or walking - this puts strain on the heart to see if any abnormalities
and changes appear) or an angiogram (a dye test in which dye is injected into the
coronary arteries via a wire fed up from your groin to show the coronary arteries and
any blockages on an X-ray)
Typically angina is a heavy, pressing or aching pain that can be anywhere in the chest
but is usually central and may radiate into the jaw or down the left arm. It usually comes
on with exertion or anxiety. The medication given for angina is a GTN spray (this is a
spray that dilates the arteries, therefore improving blood flow to the heart)
If the pain comes on without exertion or anxiety then it is unstable angina, which
indicates there may be a serious problem with the coronary arteries and needs urgent
investigation.
If the coronary arteries become too narrowed then a stent (metal cage fed up from
the groin and inserted into the coronary artery to hold the walls of the vessel open and
dilate it) or a coronary artery bypass (in which veins from the leg are taken to replace
sections of the coronary arteries that are diseased) may be needed.
Myocardial infarction
The atherosclerotic plaques in the coronary arteries can reach a level where they
rupture causing a blood clot (thrombus) to form. This cuts off blood supply to an area of
the heart and causes damage to an area of the heart muscle (because it is not
receiving oxygen) and is called a heart attack. Pain from a heart attack is generally the
same as angina but it doesn’t settle with rest and is often more severe being described
as ‘crushing’ in nature. There may be associated breathlessness, sweating and nausea.
Unfortunately sometimes a heart attack does not present typically and especially in
diabetics there can be little pain and an episode of collapse or breathlessness may be
the only sign.
If angina pain does not settle or any of the features above are present then the patient
needs to go straight to hospital, 300mg of aspirin could make a huge difference to their
survival so give aspirin if you have it.
Heart failure
Heart failure occurs when too much of the heart has become damaged for the heart
to work as efficiently. The person may develop breathlessness on exertion (not enough
oxygen getting to the heart or tissues) and oedema (fluid collection) both in their ankles
and also in their lungs, this is because the heart is not efficiently getting blood around
the circulation so their is back-pressure of fluid into the tissues and into the lungs. Severe
heart failure has a life expectancy of less than 2 years.
Rhythm problems
The electrical rhythm of the heart can be disturbed by many things including: damage
and scarring of the heart itself, genetically having extra nerve pathways, over-strain of
the heart, hormonal stimulation or medication. It may beat too fast (tachycardia) pulse
© Dr Jessica Middleton 2009
>100 beats/minute or too slow (bradycardia) <60 beats/minutes or with an irregular
rhythm.
When the heart rate or rhythm is disturbed the patient may feel palpitations (the
sensation of the heart beating in the chest) this needs to be investigated with an ECG
which can be done as a 24 hour tape to coincide with when the patient feels the
palpitations.
The most common irregular rhythm of the heart is called atrial fibrillation. This is when
the heart tissue in the atria becomes damaged and begins to generate impulses as
well as the SA node this leads to disorganized contractions of the atria which ‘fibrillate’
or quiver. In some cases this can cause a fast, irregular heart beat if these impulses
reach the ventricles and it may need to be controlled with medication or the heart
may need cardioverting (given and electric shock) in order to block these irregular
impulses.
Valve problems
If the valve cusps become damaged by infections such as rheumatic fever, bacteria
(life-threatening condition called infective endocarditis), heart disease or
the chordae tendinae rupture the valve does not close properly and blood can flow
back through it. This makes the blood flow less efficient and the heart has to work
harder to overcome it. The heart can enlarge (hypertrophy) trying to generate greater
pressures, the person may develop shortness of breath, fatigue, may have fainting
attacks and in extremes develop symptoms of heart failure. The blood flow being
disturbed as it flows back through the valves can be heard as a murmur (humming/
whooshing sound heard as listening to heart with a stethoscope). Murmurs need
investigation with an echocardiogram (ultrasound of the heart to assess the valves and
blood flow through the heart) and severe valve disease may need open heart surgery
for a replacement valve.
Energetically
The heart is energetically related to the heart chakra which represents love both of
others and yourself. It can be damaged by grief, disappointed love or not feeling
loved. It is represented by the colour green.
The Heart in chinese medicine
Dominating - Blood circulation and
meridian circulation
Controlling - The mental activities
Outside manifestation - On the face
Window - The tongue
Symptoms of heart disturbance include
insomnia, palpitations, any tongue
complaint, acne on the face, difficulty
concentrating