The heart is a hollow muscle that is about the size of an adult fist, and is found to the left of the breastbone. The heart is the most important organ in our body, as it is a complex pump, responsible for circulating blood, oxygen and nutrients around the body. It pumps blood around your body and beats approximately 70 times a minute.
The heart gets its own supply of blood from a network of blood vessels on the surface of your heart, called coronary arteries. There are many forms of coronary disease.
Coronary heart disease is the term that describes what happens when your heart's blood supply is blocked or interrupted by a build-up of fatty substances in the coronary arteries.
Angina is a type of coronary disease that affects about one in 50 people. Pain is felt in the middle of the chest, sometimes radiating down one or both arms and up into the neck or jaw. Described as a heaviness or pressure type of discomfort, it's most often felt during exertion, stress and in cold weather. Over time, the walls of the arteries can become furred up with fatty deposits, and if the coronary arteries become narrow, the blood supply to your heart will be restricted. This can cause angina (chest pains). If the coronary artery becomes completely blocked, this can cause a heart attack, also known as myocardial infarction.
Arrhythmia or irregular heart beats are also known as heart palpitations, and they are any abnormal rhythm of the heartbeat. The heart contains a natural pacemaker that triggers electrical impulses to spread over the heart, causing it to contract (the heart beat).
Cardiomyopathy means a disease of the heart muscle, rather than the blood supply or the pacemaker. There are four main types of this type of coronary disease:
- hypertrophic cardiomyopathy (MCM) where the heart muscle thickens (high blood pressure can cause this)
- dilated cardiomyopathy (DCM) when the heart muscle dilates (becomes large) and weakens
- restrictive cardiomyopathy (RCM) when chambers in the heart stiffen and restrict blood flow through the heart
- arrhythmogenic cardiomyopathy (ARVC) when fatty tissue replaces muscle in the heart and affects the electrical impulses that regulate heart beat.
Congenital heart disease is a heart abnormality that has been present from birth. Examples include failure to form the normal heart structure or holes between the chambers of the heart. Almost one in every 150 babies born in the UK has some form of congenital heart disease, ranging from the minor to fatal.
Heart valve problems - The heart is divided into four chambers, known as the right and left atrium, and the right and left ventricles. Each of these chambers has valves that prevent blood flowing backwards into the chamber it has just come from, and ensuring that blood moves forward through the heart. With this type of heart disease, the diseased heart valves that are damaged and do not open and close properly can allow blood to leak backwards or obstruct the flow of blood.
One of the underlying causes of coronary heart disease is a build-up of fatty deposits in the arteries, and these fatty deposits can rupture or split, interfering with the normal flow of blood. This causes a blood clot to form, and this clot can quickly grow, blocking one of the carotid arteries and drastically reducing the supply of blood to the heart, triggering the symptoms of unstable angina.
The key risk factors which can cause the carotid arteries to narrow are high-fat diets and cholesterol, a lack of exercise, a poor diet, and excess alcohol, smoking, high blood pressure (hypertension), diabetes, age, and family history.
If you smoke, it can damage the walls of your arteries, and blood cells (platelets) will form at the site of the damage in an attempt to repair it. This can cause your arteries to narrow. Smoking can also reduce your blood's ability to carry oxygen around your body, which increases the chances of a blood clot occurring.
If you have high blood pressure (hypertension) it will damage your arteries in the same way as cigarette smoke. Your arteries are designed to pump blood at a certain pressure. If that pressure is exceeded, the walls of the arteries will be damaged.
If you have diabetes that is poorly controlled, the excess amount of glucose in your blood can damage your artery walls. In addition, a person’s arteries tend to get narrower over time. Therefore, the older you are, the more likely it is that your arteries will have narrowed, increasing your risk of developing angina.
Coronary heart disease cannot be cured, but recent progress has meant that heart disease can now be managed more effectively. With the right treatment, the symptoms of coronary disease can be reduced and the functioning of the heart improved.
Many different medicines are used to treat coronary disease. Some of the medicines that are commonly used to treat heart conditions are outlined below.
- Low-dose aspirin and 'clot-busting' medication are used for coronary disease sufferers because blood clots in the coronary arteries are a major cause of heart attacks. A low-dose aspirin and/or a clot-busting medicine may be prescribed for you by your doctor, and this type of medicine will help prevent your blood clotting, reducing your risk of heart attack and angina.
- Anticoagulants such as warfarin are sometimes used for coronary disease sufferers to stop the blood clotting. However, they can cause bleeding, or increase bleeding from cuts or during menstruation (a woman's period).
- Statins - A high level of 'bad cholesterol' (LDL) in your blood can cause a build-up of atheroma (fatty deposits) in your arteries, increasing your risk of heart disease. If you have a high blood cholesterol level, cholesterol-lowering medicine called statins may be prescribed. They work by blocking the formation of cholesterol and increasing the number of LDL ‘receptors’ in the liver, which help to remove the LDL cholesterol from your blood. This helps to slow the progression of coronary disease, and will make having a heart attack less likely.
- Beta blockers are often used for coronary disease sufferers to prevent angina and treat high blood pressure. They work by blocking the effects of stress hormones, which make your heart beat faster and harder. This slows down your heartbeat, improves blood flow and helps your heart to pump more effectively. Beta blockers are usually taken in small doses alongside ACE inhibitors and diuretics (medicine that helps your body get rid of extra fluid). However, beta blockers are not suitable if you have respiratory problems, such as asthma, or diabetes.
- ACE (angiotensin-converting enzyme) inhibitors are commonly used to treat heart failure and high blood pressure. They block the activity of a hormone called angiotensin II, which narrows blood vessels. As well as stopping the heart working so hard, ACE inhibitors improve the flow of blood around the body.
- Angiotensin II receptor antagonists work in a similar way to ACE inhibitors, and are sometimes prescribed for coronary disease patients. They are used to lower your blood pressure by limiting angiotensin II. Angiotensin II receptor antagonists have fewer side effects than ACE inhibitors, and are often prescribed as an alternative.
- Anti-arrhythmic medicine is sometimes used to control the rhythm of your heart, if arrhythmia or heart palpitations are the coronary disease that you are suffering from.
- Nitrates are used to widen your blood vessels. Doctors sometimes refer to nitrates as vasodilators. They are available in a variety of forms, including tablets, sprays, skin patches and ointments. They work by relaxing your blood vessels, letting more blood pass through them. This lowers your blood pressure and relieves any heart pain that you have.
- Cardiac glycosides, such as digoxin, strengthen and slow the heartbeat. By making the heart muscles contract (squeeze together) more strongly, blood is pushed around the body with more force.
However if your coronary disease is due to very narrow blood vessels because of a build up of atheroma (fatty deposits), or if your symptoms cannot be controlled using medication, surgery may be needed to open up or replace the blocked arteries. Some of the main surgical procedures that can be used to treat blocked arteries are outlined below.
- Coronary angioplasty is sometimes used to treat mild coronary disease. An angioplasty opens up a blocked or narrowed coronary artery, improving the blood flow to the heart.
- A coronary artery bypass is a procedure that allows the blood flowing through the coronary artery to bypass (get round) the part of the artery that is blocked.
- Heart transplant - In a small number of cases, when the coronary disease means that the heart is severely damaged and medicine is not effective, or when the heart becomes less efficient at pumping blood around the body (heart failure), a heart transplant may be needed. A heart transplant involves replacing a heart that is damaged or is not working properly with a healthy donor heart.
- Laser surgery is a technique that creates channels in the heart to allow blood to flow more easily. Using a catheter (thin wire) with a laser attached, the surgeon makes lots of tiny holes in your heart muscle. The holes encourage new blood vessels to grow in the diseased heart muscle. This procedure is sometimes carried out on its own, or in conjunction with coronary bypass surgery.