Heart Attacks, Angina and Pig Hearts
Below, we've got a great guest article that outlines the session plan for a meeting on cardio anatomy and physiology in the
context of hearts attacks and angina.
What is a heart attack?
In my experience of training first aid, I have found that many first aiders – new and experienced alike – do not have a basic understanding
of what a heart attack is and what causes it. This interactive session uses pigs’ hearts to learn about heart attacks and some important
Why should people care about physiology?
I hate it when people overcomplicate first aid. First aid should focus on having a good grasp of the basics, and adding additional waffle is
likely to confuse situations which should be simple.
However, this doesn’t mean that learning should stop at the absolute basics. Having a concise and focussed understanding of some of the principles
behind important illnesses…
Who is this for?
- is interesting
- reinforces and contextualises school work (e.g. biology) for younger first aiders
- helps people remember signs and symptoms because they understand them
- helps people understand how medication should be given (in this case GTN)
- many more reasons!
What will you learn?
- Basic heart anatomy and physiology
- What a heart attack is
- What angina is
- How GTN works
As this activity involves pig hearts, it is likely to be unsuitable for several groups of people including (but not limited to):
Consider checking if people in your group are comfortable handling pig hearts. If not, see the note below about alternatives. Also be aware that
heart attacks are likely to be a sensitive topic for some people in the group. Make sure that the students know that they can step out of the session at any time.
- Vegetarians and vegans
- People of Muslim or Jewish faith
The pig hearts can be purchased from any local butchers if you ask a few days in advance. They cost around £1 each. I find using foil food platter trays to be a
good way to present the hearts so you don’t have to rest them on your tables! These normally cost £1.50 for a few from Wilko. Roasting trays are also a good idea.
- Pig hearts (1 between 4 students)
- Waste bags
- Foil trays to put hearts on
- Disinfectant wipes
How I run this session
I have tried a few different ways of running this session and found that this is the most effective.
First, I put together a PowerPoint of material (I've given the structure at the bottom of this article). This gives a really good background into the theory before we
launch into the practical. This normally takes 15-20 minutes. The one thing that you may want to discuss is that the blood vessels of the heart are called ‘coronary vessels’.
I have found that this confuses some groups, so use that terminology with caution.
This is the point that you bring out the pig hearts!
Referring to the PowerPoint slide with the pig heart, show the students the coronary vessels. Here is an example below:
You can then get your students to split into groups and:
- Find the vessels on their hearts
- Discuss which parts of the heart are likely to infarct
- Discuss which parts of the vessels would be worst to have a blockage? And best?
Notes, tips and alternatives
- You can get atherosclerosis anywhere! This can include places like your legs. People who smoke a lot get it especially badly and sometimes have to get
amputations because the blood flow is so bad.
- Having angina means that you are at a higher risk of having a heart attack.
- Pig hearts are quite a good representation of human hearts. Human hearts are a bit bigger – about the size of a fist.
- Why do we get left arm pain? The nerve which senses the area around the heart joins up with some of the nerves from your arm, which confuses some of the signals.
- If you have students who don’t want to use a real heart, you could try:
- Printing on to card and cutting it out
- Using a model heart (try borrowing one from a nearby GP – I have found that most GPs have one and are quite generous about helping).
The powerpoint structure
- Introduction to chest pain
- Ask people what causes they know for chest pain
- Focus in on heart conditions angina and heart attacks
- Risk factors for heart attacks (here is a great resource: https://www.bhf.org.uk/heart-health/risk-factors)
- Basic heart physiology
- The heart is a pump that moves blood around the body
- Blood contains lots of things, the most important being oxygen.
- The blood goes all over the body through blood vessels called arteries and veins
- The oxygen therefore able to get to all the different parts of the body
- Lots of people don’t know is that the heart also has its own blood vessels so that it can be kept full of oxygen
- Introduction to atherosclerosis
- Keep on relating this to the risk factors mentioned earlier
- Your blood also carries fats
- Sometimes the fat gets stuck to the inside of blood vessels
- If this happens lots, the blood vessels get narrower (a bit like leaves clogging guttering)
- This is called atherosclerosis
- If the blood vessels become very narrow, they can restrict blood flow
- This means that the parts of the body that need oxygen don’t necessarily get it
- This is what happens in angina:
- When you exercise or exert yourself, your heart beats faster
- Your heart needs more oxygen because it is working harder
- The narrowing of blood vessels around the heart means that the parts of the heart cannot get enough blood
- This means the heart cannot get enough oxygen
- This causes the severe chest pain
- How can we use this information?
- If we get the person to rest, the heart will slow down
- The heart will then be working less hard
- It will need less oxygen
- It is less of a problem that the blood flow is restricted
- No chest pain
- Angina patients take GTN to help them in an attack
- GTN is Glyceryl Trinitrate
- This is a vasodilator (“Vaso” means vessel, “dilate” means to make bigger)
- Therefore, GTN, as a vasodilator, makes the blood vessels bigger.
- This is useful in an angina attack because it reduces the narrowing of the vessels
- This means that blood flow is not restricted
- This means that the heart is not starved of oxygen
- That is how GTN works!
- The problem is that GTN doesn’t just affect your heart’s blood vessels
- It affects all vessels and makes them dilate all around the body
- This means there is now a situation where your blood vessels are bigger, but the amount of blood you have is the same
- This reduces your blood pressure (think about pouring some water from a small cup to a larger cup – the larger cup will be less
full than the small cup. It is the same principle here.)
- The sudden drop in blood pressure can make you dizzy and maybe faint.
- Now we know that you should give GTN to people only while they are sitting down!
- Heart attack
- Sometimes, the fatty zones on the arteries become large and unstable
- If you are unlucky, they rupture/break
- This causes the whole blood vessel to be blocked
- This means no blood can get through
- This is extremely bad with the heart’s blood vessels
- Like angina, the lack of blood causes the heart to be starved of oxygen
- It is worse in a heart attack because there is NO blood flow rather than only some
- After a few minutes, parts of the heart start to die
- The medical name for a heart attack is a myocardial infarction
- “Myo” means muscle, “cardio” means heart”, “infarction” refers to an obstruction to blood supply causing tissue death
- Myocardial infarction, or ‘MI’ means death of heart muscle because of an obstruction to blood supply.
- If enough heart muscle dies, you can have a cardiac arrest (This is different to a heart attack)
- A cardiac arrest is when the heart stops beating or when it stops beating effectively
- There are lots of causes of cardiac arrest – heart attack is just one of them!
- Bring up a picture of a pig heart (as explained above)