The Heart

The Heart

The human heart is the second most important organ in the human body. Without the human heart pumping, the body would not receive blood to the other organs and systems of the body that keep it alive and working. The heart is so important that while you are alive it should never stop, even while you are resting and asleep!

Did you know……?

The heart beats (on average):

72 times per minute,
100,000 times per day,
36,500,000 times a year,
2,500,000,000,000 times in a lifetime (that’s 2.5 billion!).

This goes to show how important the heart is and what an amazing job it does, even while we are asleep.

Where is the heart located?

There is an age-old myth that the heart is located on the left side of the chest, this however is not factually accurate, and if it was on the left-hand side of the chest, it would mean that Cardio-Pulmonary Resuscitation (CPR) would be ineffective as the First Aider’s hands would be missing the heart!

In fact, the heart is situated right in the middle of the chest, and roughly in line with the thoracic vertebrae of the spine covering T5 to T8.

A view of the spine complete with sections detailed.

The thoracic vertebrae are the middle segment of the vertebral column as shown in the diagram to the right, coloured blue for easy recognition. The vertebral column is important as the back of the heart sits near to this, with the front of the heart sitting behind the sternum and the ribs. This is why we place our hands on the sternum to apply pressure to the heart during CPR.

The largest part of the heart usually hangs to the left-hand side, which now makes the age-old myth make sense! However, there are times when the heart will hang to the right-hand side of the human body. To accommodate the heart the 2 lungs are different sizes, with the left-hand lung being smaller with a cardiac notch in its border to ensure the heart can be accommodated. Typically, the left-hand side of the heart is stronger than the right and this also explains why the heart is felt more predominantly on the left-hand side of the body, this is the part of the heart that delivers blood to all parts of the human body.

Shape of the heart

Typically drawn shape of the heart

The heart is often seen by many to represent the centre of the body because of its importance as well as representing love and other such emotions. It is generally drawn and depicted like the representation above, however the heart is not this shape. A more accurate description of the heart would be cone-shaped, with its base positioned upward and the point tapering down to the apex of the heart.

An adult heart has a mass of 250 to 350 grams (9 to 12 oz). It is often described as the size of the fist which roughly measures 12 cm (5 in) in length, 8 cm (3.5 in) wide and 6 cm (2.5 in) thick, however the description of the heart as a fist is often disputed as the heart is likely to appear slightly larger than this. It is true that well-trained athletes may have larger hearts than this description as well, due to the effects of exercise on the heart muscle.

Below, is a more accurate diagram of the heart:

Diagram of the heart

Anatomy of the heart

The heart has 4 chambers contained inside, as well as 4 heart-valves. These consist of 2 upper atria and 2 lower ventricles. What is the purpose of the atria and ventricles?

Atria – The chambers that receives blood.

Ventricles – The chambers that dispense blood.

Each atrium and ventricle are separated by an atrioventricular valve, while the other 2 valves rest at the exit of the ventricle.

Often the left ventricle and left atrium are referred to as the left heart, and similarly the right ventricle and right atrium are referred to as the right heart.

The Heart Valves

The main function of the heart valves is to ensure that the blood only flows one way through the heart. It is the opening and closing of the heart valves that give the heart its very familiar du-dum sound. The 4 valves in the heart are called:

Atrioventricular Valves (separating the ventricle and atria):

  • Mitral Valve,
  • Tricuspid Valve.

Semilunar Valves (at the exit of the ventricles, in the arteries leaving the heart):

  • Aortic Valve,
  • Pulmonary Valve.

The mitral and aortic valves are located in the left heart, and the tricuspid and pulmonary valves are located in the right heart.

The diagram below shows you how the blood enters the heart and is then processed through the heart to be redelivered round the body again:

Used with thanks to Wapcaplet- Own work, CC BY-SA 3.0,

How many times a minute does the heart beat per First Aid age range?

As discussed earlier the heart is constantly beating, and although we have given the average beats per minute above it is important to remember that the heart will beat differently according to your age and body size as follows:

per Minute
(Under 1 year)
110 to 140
(1 to Onset of Puberty)
90 to 110
(Puberty to death)
60 to 90

Heart Complications

The heart is an amazing piece of kit as we have highlighted, however it does often suffer from complications. Here we look at 5 different complications:

  • Coronary Heart Disease
  • Heart Failure
  • Atrial Fibrillation (AF)
  • Angina Pectoris
  • Heart Attack.
Coronary Heart Disease

Coronary Heart Disease (CHD) is a major killer in both the UK and worldwide. It is sometimes called Ischaemic Heart Disease. The main symptoms of CHD are:

  • Angina Pectoris,
  • Heart Attacks and
  • Heart Failure.

We will consider these main symptoms in due course. It is also important to note not all people will have the same symptoms as another person and some may have no symptoms before CHD is diagnosed.

Coronary heart disease describes the heart’s blood supply being blocked or interrupted by a build up of fatty substances in the coronary arteries. This is generally caused by a number of factors including lifestyle choices as follows:

  • Smoking,
  • High cholesterol,
  • High blood pressure,
  • Diabetes.

This list is not exhaustive.

It is important that if you feel that you are unwell, and unsure what is going on with your heart, that you make an appointment to see your GP as s/he will be able to refer you to specialists who will carry out tests to diagnose, or otherwise, CHD and then can advise how to keep your heart well, which may include simple lifestyle changes and/or medication.

It has been noted in many medical articles over recent times that maintaining a healthy heart can also help to avoid other life illnesses which include stroke and dementia.

Heart Failure

Heart failure is a horrible sounding term which doesn’t accurately describe what is happening to the heart.

Heart failure means that the heart is unable to pump blood around the body properly, usually because it has become stiff or too weak to function in its normal way. The name suggests that the heart has failed to work or stopped which is actually incorrect. It just means that the heart needs some help for it to work better, most commonly affecting older people.

Sadly, heart failure is not an illness that can be cured, however it can be controlled for many years.

Heart failure can develop quickly which is called acute heart failure or can develop over a long period of time usually referred to as chronic heart failure. Normal signs and symptoms are:

  • Breathlessness after exercise or at rest,
  • Feeling tired most of the time,
  • Swollen legs/ankles,
  • Finding exercise physically exhausting,
  • Persistent cough,
  • Dizziness,
  • Fast heart rate.

It is advisable for you to see a GP if you experience persistent or worsening heart failure symptoms, however you should call 999/112 for an ambulance or go straight to A&E should you experience sudden or very severe symptoms.

Like coronary heart disease, treatments can be simply lifestyle changes or sometimes the casualty will require an operation to help allay the symptoms of heart failure.

Atrial Fibrillation (AF)

Atrial fibrillation (AF) is a heart condition that causes an irregular and often an abnormally fast heart rate, sometimes an atrial fibrillation event can cause the heart rate to be over 100 beats per minute. This can cause:

  • Dizziness,
  • Shortness of breath,
  • Tiredness.

The person who has atrial fibrillation may notice heart palpitations, where the heart feels like it is pounding, fluttering or beating irregularly, which may last for a few seconds or even minutes. However, some people may not even feel any symptoms at all.

Atrial fibrillation is the most common heart disturbance illness in the UK with around 1 million people affected by it. Atrial fibrillation can affect anyone of any age, however it is more likely to affect older people with the statistics showing that it affects 7 in a 100 people over the age of 65; it is more common in men than women.

When in atrial fibrillation the heart’s upper chambers (atria) contract randomly and sometimes so fast that the muscle wall is unable to relax properly between its usual contractions, reducing the efficiency and performance of the heart. It occurs when abnormal electrical impulses start firing in the atria, overriding the heart’s pacemaker, who can no longer control the heart rhythm.

The good news is that atrial fibrillation is not life-threatening but can be very uncomfortable and will require treatment. The best way to help atrial fibrillation is to see a doctor who can then suggest the best course of treatment for the condition.

Angina Pectoris

Angina is a condition which is usually caused by a build-up of cholesterol plaque on the inner lining of the coronary artery.

What is Cholesterol?

Cholesterol is a fatty chemical which is a part of the outer lining of the cells of the body. Cholesterol Plaque however is a hard, thick substance caused by deposits of cholesterol onto the artery wall, which over time builds up causing a narrowing and hardening of the coronary artery.

During periods of excitement and/or exercise the heart, to maintain its normal function, needs more oxygen; the problem however is that the coronary artery is now narrower and therefore cannot increase the blood supply to the heart to meet the heart’s requirement. As a result of this an area of the heart will now suffer from a lack of oxygen, causing the casualty to experience chest pains and other symptoms.

Usually, an angina pectoris attack occurs with exertion and will subside with rest. However, if the narrowing of the artery reaches a critical level, angina at rest may occur, this is called unstable angina. A casualty who has unstable angina has a high risk of having a heart attack in the near future.

We will examine the symptoms and treatments of angina below along with heart attack.

Heart Attack

A heart attack occurs when the surface of cholesterol plaque in the coronary artery ruptures and the contents leak out into the artery itself, this will lead to a blood clot which results in the artery becoming blocked and a death of an area of the heart muscle.

It is important that we remember that all heart attacks are different, and sometimes will not display a symptom at all, these are called silent heart attacks; these don’t even provide the casualty with chest pain. Diabetic and elderly people are more at risk of a silent heart attack.

Unlike angina pectoris, the death of the heart muscle is permanent and will not be relieved by rest.

Signs and symptoms of Angina Pectoris and Heart Attack compared:

Heart Attack Vs. Angina Pectoris Angina Pectoris Heart Attack
Onset Sudden,
Usually during exertion,
Stress, Extreme weather.
Can occur at rest.
Pain Vice like squashing pain,
Usually described as a dull pain,
Tightness or pressure on the chest,
May be mistaken for indigestion.
Vice like squashing pain,
Usually described as a dull pain,
Tightness or pressure on the chest,
May be mistaken for indigestion.
Location of Pain Central chest pain,
Can radiate into EITHER arm
(usually the left),
Neck, Jaw, Back, or Shoulders.
Central chest pain,
Can radiate into EITHER arm
(usually the left),
Neck, Jaw, Back, or Shoulders.
Skin Pale,
May be sweaty.
Pale, Grey colour,
May swear profusely
Pulse Variable
(depending on which area has lack of oxygen),
Becomes irregular,
Missing beats.
(depending on which area has lack of oxygen),
Becomes irregular,
Missing beats.
Other signs and symptoms Shortness of breath,
Shortness of breath,
Dizziness, Nausea, Vomiting, Sense of impending doom!
Factors giving relief Resting,
Reducing stress,
Taking prescribed glyceryl Trinitrate (GTN) medication (spray).
Taking prescribed glyceryl Trinitrate (GTN) medication (spray) may give partial or no relief.

Based on the Qualsafe First Aid Made Easy grid

Treatment of Angina Pectoris and Heart Attack

  • Sit the casualty down, make them comfortable or use the half ‘W’ position:
    • Back against a wall, legs bent, feet flat on the floor (Attend one of our courses and we will demonstrate this).
  • If they have it, encourage them to take their own prescribed GTN medication.
  • Reassure the casualty, remove any causes of stress and anxiety if this possible.
    • Offer the casualty an aspirin tablet to chew slowly; this may help limit damage to the heart. (Only do this if the casualty is over 16 and is NOT allergic to aspirin.)
  • Monitor the casualty’s Airway, Breathing and Circulation.

If the casualty has become unconscious it will usually mean that the heart has stopped altogether. You must be prepared to resuscitate.

Why does aspirin work?

Aspirin is a drug that is designed to reduce the blood’s ability to clot. By chewing the tablet, the casualty is absorbing the drug quicker into their bloodstream, allowing it to work faster. Ideally use a 150mg or a 300mg chewable or soluble aspirin.

When to call 999/112

You should call 999/112 immediately if:

  • You suspect a heart attack,
  • The casualty has not been diagnosed as having angina,
  • The symptoms the casualty is experiencing are worse or different to their normal attacks,
  • Angina pain has not been relieved from resting and taking their GTN spray after 15 minutes,
  • Angina pain has woken the casualty from their sleep,
  • Angina pain has come on whilst the casualty is at rest,
  • You are in any doubt.

For more information on heart attack or angina pectoris as well as for handy hints and tips, why not attend one of our adult based First Aid courses? We look forward to welcoming you on a course.

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