How Do I
Know If I Am Having a Heart Attack?
by: Dr Tony Neaverson MB, BS
Most patients have symptoms prior to an actual heart attack –
generally a “tightness” behind the breastbone, which generally is caused
by an increase in heart rate. The coronary arteries fill in between
heart beats therefore anything which increases your heart rate will
reduce the time your coronary arteries have to provide blood flow to the
heart muscle- the myocardium. Once the heart muscle is deprived of
oxygen it becomes irritable leading to palpitations and, if not
relieved, death of the muscle.
Surrounding the dead muscle is a variable sized area of heart muscle at
risk of dying because of inadequate oxygen supply – this condition is
known as myocardial ischaemia.
The heart rate is under the control of the autonomic nervous systems,
which, in the case of the heart, is driven by adrenaline the so-called
“flight or fight” hormone.
Adrenaline acts at various sites of the body
- On the sinus node in the heart which controls rate to increase
- On the bronchial tubes in the lung to cause them to dilate
allowing greater flow of air into the lungs
- On the small arteries in the skin and gut to constrict (narrow)
reducing blood flow to these areas and making more blood available
to the muscles- to fight or fly
- Increases the blood sugar by increasing breakdown of glycogen to
glucose, important food for the muscles to contract better.
Whilst increased adrenaline production is common with exercise it
also occurs in states of shock, fear, or anger producing gooseflesh and
sweating (remember the first time you saw the shower scene in the
Hitchcock Movie Psycho).
As well as increasing the heart rate adrenaline may cause cardiac
irregularity, increased blood pressure, or palpitations. It is this
irregularity which may lead the heart to chaotic beats and finally
fibrillation and death.
This is the first symptom of a heart attack in about 20% of people –
sudden death – the victim just collapses to the ground. Whilst he may
gasp a few breaths he has no cardiac output- no blood is leaving his
heart- he is pulseless.
This terminal condition (ventricular fibrillation) is very easily
treated by first aid measures and cardiac shock- termed defibrillation.
Nowadays many areas which have high populations (or as in aeroplanes,
confined areas) have people friendly defibrillators available which only
shock patients who have rhythms which are treatable by shock. These
machines have easy instructions and any bystander who can read can apply
the electrodes and save the patient’s life.
Often people wrongly refer to this cause of death as a massive heart
attack- it takes some time (often up to an hour) to die from a massive
heart attack. In this case the heart attack causes such significant
damage to the main ventricle of the heart as to reduce blood pressure to
critically low levels and death results.
Cause of Heart Attacks
The pathological cause of heart attacks is a clot of blood, which
forms over an area on the lining of a coronary artery which, is “ready”
for a clot to form – this area is termed a vulnerable plaque.
It was previously thought that clots developed on the lining of arterial
walls that had become calcified and thickened - it is now known that
rarely are these areas the sites of clots.
Calcification and deposition of cholesterol within the arterial wall
reduces the lumen size and therefore flow of blood through this section
of the artery is likewise reduced. This reduced flow may be sufficient
to provide enough oxygen to the heart muscle during rest or light work.
However once the heart is required to work harder the blood flow is
insufficient to provide enough oxygen to the heart muscle and symptoms
Angina- Pectoris and Decubitus
When the heart muscle receives insufficient oxygen it produces lactic
and pyruvic acids and these produces the tightness in the chest known as
angina the type of angina which occurs during exercise is termed Angina
The obvious treatment is to reduce the heart work by ceasing whatever
activity has caused the heart rate to rise.
Whilst typically angina pectoris occurs as tightness in the chest it may
move up into the throat or down one or both arms. Occasionally it may
only occur in the teeth or in the back between the shoulder blades.
Patients may describe it as a “weight on my chest” or “constriction”.
Occasionally the only symptom may be acute breathlessness.
The cardinal feature is the relation to increased heart work and its
relief by stopping activity. In addition one should use a trintrin
preparation. If pain is present use another dose after five minutes or
so and repeat twice.
The treatment of angina is beyond the scope of this article however
drugs which reduce the work the heart has to do (like putting a governor
on your heart) are most effective and as they block the action of
adrenaline are termed betablockers.
Drugs, which dilate the coronary arteries (trintrins), are also helpful.
These come as patches, tablets for sucking, sprays for inhalation or as
solutions for intravenous use in hospital. These should be used only
when the tightness is present and not when you feel giddy or weak as
they will reduce blood pressure and may cause you to faint. These also
dilate all arteries and therefore may cause headache.
Trintrins are particularly dangerous when used in conjunction with some
of the newer drugs for erectile dysfunction eg viagra and these must not
be used within 24 hours of each other
Spasm of the coronary arteries may also cause reduction in blood flow to
the heart. Everyone has some degree of spasm within their bodies and
angina is generally due to mixture of both atheroma and spasm.
However angina, which occurs at rest particularly at night around 2.0am
waking the patient, is due to vasospasm and is termed angina decubitus.
The symptoms are similar to angina pectoris but in this case it is spasm
of the artery and the treatment is not betablockade therapy but a group
of drugs called calcium antagonists. These drugs relieve the spasm of
Should the pain be prolonged and not relieved by rest and trintrin
therapy the term unstable angina is used.
In this case the pain is more severe and often associated with an
increase in sympathetic overactivity. Symptoms such as sweating, nausea,
vomiting, palpitations, faintness or a feeling of wanting to faint (presyncope),
or even syncope are common.
This is a medical emergency and an ambulance should be called without
delay, as it is impossible to differentiate unstable angina from a heart
attack without electrocardiograph and blood studies.
If you believe that you may have this syndrome whilst waiting for the
ambulance chew a whole aspirin tablet.
This condition is generally associated with a clot being formed within
one of the main coronary arteries and hospitalisation is necessary so
that a definitive diagnosis may be made and urgent treatment to protect
the heart from damage instituted.
Angina is often confused with indigestion and many patients
rationalize that whilst they may consider the pain could be angina it
“simply cannot happen to me’ and it is probably only indigestion or just
One eminent Professor of Cardiology writing in one of the journals
described how he waited for eighteen hours before going to Hospital as
he thought it “ was simply bad indigestion”. He finished up with bypass
Indigestion is generally in the pit of the stomach burning in nature,
often relieved by belching or by drinking a glass of milk or alkali. It
has no relation to exercise, rarely referred to the arms or back, and
may come up into throat as a burning sensation. Trintrins have no
Hiatus hernia or oesophageal reflux may mimic vasospastic angina as they
both occur at night when the patient is prone.
Some patients, generally those with high pain thresholds, may have
myocardial ischaemia which is entirely asymptomatic.
Rarely patients may be found with classical electrocardiographic changes
of a heart attack without remembering anything remotely like the
symptoms, which are noted above.
On a treadmill exercise test these patients may develop changes on their
cardiograph, which are diagnostic of myocardial ischaemia. They may
develop high blood pressure or more dangerous, a fall in blood pressure
during exercise without any actual pain.
These patients are very difficult to treat, as, unlike most of us, they
do not get chest tightness of pressure before they develop dangerous
cardiac abnormalities. These people require invasive or nuclear studies
to ascertain the workload that causes trouble. They can then be warned
to control their work level.
Heart Failure and Cardiac
Patients in their senior years may develop heart failure without any
pain or tightness. The Electrocardiographic changes of a previous heart
attack are found on routine examination.
Atrial fibrillation, a not uncommon rhythm disturbance, often has
myocardial ischaemia as its underlying cause, particularly in the
elderly. This irregularity results in a reduction in the output from the
left ventricle (stroke volume). As blood continues to fill the ventricle
from above the lower output results in the heart becoming distended with
Heart muscle like all other muscles when stretched contracts with
greater strength thereby increasing the output. The patient is unaware
of anything the matter with his heart until an xray is taken showing an
enlarged heart . (Compensated Heart Failure)
However if the reason for the reduction in stroke volume remains then
eventually (when the heart cannot enlarge further) pressure within the
ventricle rises and is passed backwards through the atrium and on into
the pulmonary arterioles causing fluid to move into the air sacs of the
lungs and the patients notices increasing shortness of breath
breathlessness. (Decompensated Heart Failure)
- Never take chest pain lightly - you might wake up dead !
- Learn a plan and keep to it.
- It is only at an Emergency Centre that you can get immediate
- Most Heart Attacks who are destined to die do so within the
first few hours. Don’t Delay.
- Special Treatment to reduce the residual damage to your heart is
most effective when given early. Particularly within three hours of
the onset of pain.
- You will not be laughed at for going to the Hospital with
- Remember no one can exclude a Heart Attack from a Severe anginal
pain without ECG and blood tests
Heart Disease Symptoms Can Save Your Life
There are millions of Americans that have heart disease and could take
some helpful measures to prevent it from getting worse if they only knew
they had a heart disease.
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About the Author:
Dr Tony Neaverson MB,BS (Qld) MRCP (London),FRACP, is a Preventive
Cardiologist. He is currently Director of the Heart Disease Prevention
Centre at Noosa Hospital in South East Queensland. An authoritative
website with information on all aspects of Heart Disease is available on