What is coronary artery disease and how does it affect the heart?
Coronary artery disease (often called coronary heart disease or CHD) is one of the most common cardiovascular conditions in the UK. It occurs when the heart’s blood supply becomes blocked or interrupted by a build-up of fatty substances. Understanding this process is essential because it directly impacts how efficiently your heart can pump oxygen-rich blood around your body. This article outlines exactly what happens inside the arteries and how it affects your long-term heart health.
What We’ll Discuss in This Article
- The medical definition of coronary artery disease (CAD).
- How atherosclerosis affects blood flow to the heart muscle.
- Common symptoms such as angina and breathlessness.
- The main causes and risk factors, including lifestyle habits.
- How to distinguish between angina and a heart attack.
- When to seek emergency medical help.
What is coronary artery disease?
Coronary artery disease is the narrowing of the coronary arteries due to a build-up of fatty deposits known as atheroma. This process, called atherosclerosis, restricts the flow of oxygen-rich blood to the heart muscle. Over time, the arteries become harder and narrower, which can lead to angina, heart attacks, or heart failure.
Understanding atherosclerosis
The coronary arteries are the major blood vessels responsible for supplying the heart muscle with oxygen and nutrients. In a healthy heart, these vessels are smooth and elastic, allowing blood to flow freely.
In coronary artery disease, the inner lining of these arteries becomes clogged with fatty material (atheroma). This process is gradual and can start years before symptoms appear. As the atheroma builds up, the space inside the artery narrows, making it difficult for enough blood to pass through, especially when the heart is working hard during exercise or stress.
How does it affect the heart?
Coronary artery disease affects the heart by limiting the oxygen supply to the heart muscle (myocardium). When the heart beats faster and demands more oxygen, the narrowed arteries cannot deliver enough blood, causing ischaemia. This lack of oxygen causes chest pain (angina) and, if a blockage becomes complete, results in permanent heart muscle damage.
The impact on heart function
The heart requires a constant supply of oxygen to pump effectively. When this supply is reduced, the heart muscle must work harder to meet the body’s needs.
- Reduced efficiency: The heart may struggle to pump blood efficiently, leading to fatigue and breathlessness.
- Electrical instability: Ischaemia can affect the heart’s electrical system, potentially causing irregular heartbeats (arrhythmias).
- Muscle damage: If blood flow is completely blocked, usually by a blood clot forming on a ruptured piece of atheroma, part of the heart muscle begins to die. This is a myocardial infarction, or heart attack.
Symptoms of coronary heart disease
The symptoms of coronary heart disease vary significantly between individuals. Some people may have no symptoms at all until they experience a sudden heart event, while others experience regular discomfort.
Common signs
- Chest pain (angina): Often described as a heaviness, pressure, tightness, or squeezing sensation in the centre of the chest.
- Radiating pain: Discomfort may spread to the arms (usually the left), neck, jaw, back, or stomach.
- Breathlessness: Feeling short of breath, particularly during physical activity or stress.
- Feeling faint: Lightheadedness or dizziness.
- Nausea: Feeling sick, sometimes accompanied by a cold sweat.
Safety Note: If you experience severe chest pain that does not go away after resting, call 999 immediately.
Causes of coronary artery disease
Coronary artery disease is primarily caused by atherosclerosis. While the exact trigger for this process varies, it generally involves damage to the inner lining of the coronary arteries.
Factors contributing to arterial damage
Once the artery wall is damaged, fatty deposits, cholesterol, cellular waste, and calcium begin to accumulate at the injury site.
- Cholesterol accumulation: High levels of low-density lipoprotein (LDL) cholesterol can deposit in the artery walls.
- Inflammation: The body’s immune response to arterial damage can increase plaque build-up.
- Thrombosis: If the hard outer shell of a plaque cracks (ruptures), blood cells called platelets clump together to form a clot, which can block the artery.
Risk factors and triggers
Several lifestyle and genetic factors increase the likelihood of developing coronary artery disease. Addressing these factors is a key part of managing heart health.
- Smoking: Chemicals in tobacco smoke damage the lining of the arteries and increase the risk of clotting.
- High blood pressure: Puts extra strain on the heart and arteries, accelerating atherosclerosis.
- High cholesterol: Increases the amount of fatty material available to form atheroma.
- Diabetes: High blood sugar levels can damage blood vessels and nerves that control the heart.
- Inactivity: A sedentary lifestyle contributes to high blood pressure and cholesterol.
- Obesity: Being overweight increases the strain on the heart and risk of diabetes.
- Family history: A strong family history of premature heart disease can increase risk.
Angina vs heart attack: What is the difference?
It is vital to distinguish between angina (a symptom of CAD) and a heart attack (a medical emergency caused by CAD).
Angina
- Cause: Temporary reduction in blood flow, usually during exertion or stress.
- Duration: Typically lasts a few minutes.
- Relief: Usually improves with rest or medication (such as a GTN spray).
- Sensation: Discomfort, pressure, or tightness.
Heart Attack
- Cause: Sudden, complete blockage of a coronary artery (often a blood clot).
- Duration: Lasts longer than 15 minutes and does not resolve with rest.
- Relief: Does not improve with standard angina medication; requires emergency hospital treatment.
- Sensation: Crushing, severe pain, often with sweating, nausea, and a sense of impending doom.
Conclusion
Coronary artery disease is a condition where fatty deposits narrow the arteries, restricting oxygen supply to the heart. It affects heart function by causing angina, reducing pumping efficiency, and increasing the risk of heart attacks. Recognising the symptoms, such as chest tightness and breathlessness, and understanding the risk factors are essential steps in managing your heart health.
If you experience severe, sudden, or worsening symptoms, call 999 immediately.
What is the main cause of coronary artery disease?
The main cause is atherosclerosis, where fatty deposits called atheroma build up in the coronary arteries, narrowing them and restricting blood flow.
Can coronary artery disease be cured?
It cannot be cured completely, but it can be managed effectively with lifestyle changes, medication, and sometimes surgery to improve blood flow.
Is angina the same as a heart attack?
No, angina is temporary chest pain caused by reduced blood flow, whereas a heart attack is a medical emergency caused by a complete blockage of blood supply to the heart.
How is coronary heart disease diagnosed?
Doctors use tests such as an electrocardiogram (ECG), echocardiogram, blood tests, and coronary angiography to assess blood flow and heart structure.
Can stress cause coronary artery disease?
Chronic stress is a risk factor as it may lead to high blood pressure and unhealthy lifestyle habits, which contribute to the development of the disease.
Does exercise help with coronary artery disease?
Yes, regular, moderate physical activity strengthens the heart and improves blood circulation, but you should follow medical advice on safe exercise levels.
Authority Snapshot
This evidence-based guide adheres strictly to NHS guidelines on Coronary heart disease and NICE clinical guidelines, providing clear, safe, and factual information on the definition and impact of coronary artery disease. The content has been authored and reviewed by professionals, including Dr. Rebecca Fernandez, a UK-trained physician with extensive experience in cardiology and emergency medicine. This article explains the causes of heart ischaemia, reinforces safety protocols, and does not offer diagnostic advice, ensuring readers receive accurate, trustworthy public health information.
