Cardiovascular disease (AQA GCSE Biology Combined Science): Revision Notes
Cardiovascular disease
What is cardiovascular disease?
Cardiovascular disease is a general term for conditions that affect the heart or blood vessels. These diseases are non-communicable - this means they cannot be passed from one person to another like infectious diseases can.
Most cardiovascular diseases develop slowly over many years. They gradually get worse if left untreated.
The slow progression of cardiovascular diseases means that early detection and lifestyle changes can significantly impact the outcome. Many conditions can be managed effectively when caught early.
Coronary heart disease
What happens in coronary heart disease
Fat deposits build up inside the coronary arteries. These are the blood vessels that supply the heart muscle itself with blood and oxygen.
When fatty material blocks these arteries, it causes several problems:
- Less blood flows to the heart muscle
- Less oxygen reaches the heart muscle
- The person experiences chest pain
- This can lead to heart attacks or even death
Treatment with stents
A stent is a small wire frame that doctors can insert into a blocked artery.
Worked Example: How Stent Insertion Works
Step 1: The stent is placed inside the damaged blood vessel Step 2: A tiny balloon expands the stent Step 3: The balloon is then removed Step 4: The stent stays in place, keeping the artery open Step 5: Blood can now flow more freely to the heart
Faulty heart valves
What happens when heart valves are faulty
Heart valves control blood flow through the heart. When they don't work properly:
- The valves may not open fully
- The valves may develop leaks
- The heart becomes less efficient at pumping blood
- Blood flow to the lungs and body decreases
- This causes tiredness and breathlessness
- Without treatment, it can lead to death
Treatments for faulty valves
Doctors can replace faulty heart valves with:
Mechanical valves - made from metals or artificial materials Biological valves - taken from human donors, cows, or pigs
Critical Treatment Information: Patients who receive mechanical valves must take drugs to prevent blood clots. Those with biological valves may need drugs to prevent their immune system rejecting the new valve.
Heart failure
What is heart failure
Heart failure happens when the heart cannot pump enough blood to meet the body's needs. The heart muscle becomes too weak or damaged to work properly.
Treatments for heart failure
Heart transplants - replacing the whole heart with a healthy one from a donor Combined heart and lung transplants - for patients with problems in both organs
Artificial hearts are sometimes used to:
- Keep patients alive while waiting for a transplant
- Give the patient's own heart time to rest and recover
These treatments are very expensive and carry significant risks.
Treatment options and considerations
Artificial pacemakers
An artificial pacemaker is a small device placed under the skin. It sends electrical signals through a wire to the heart. This helps correct irregular heart rhythms and keeps the heart beating at the right rate.
Drugs and their effects
Many cardiovascular diseases can be treated with drugs. However, most medications have side effects.
Worked Example: Statins
What they do: Statins are drugs that lower blood cholesterol levels
How they help: Lower cholesterol means less fatty material builds up in arteries, reducing the risk of blockages and heart attacks
Side effects: Muscle pain and increased diabetes risk
Research findings: Studies show the benefits usually outweigh the risks
Key Points to Remember:
- Cardiovascular disease affects the heart and blood vessels and cannot be passed between people
- Coronary heart disease is caused by fatty deposits blocking the heart's blood supply - treated with stents
- Faulty heart valves can be replaced with mechanical or biological alternatives
- Heart failure may require transplants or artificial hearts to keep patients alive
- All treatments have benefits and risks that doctors must carefully consider