16834 Cardiac Computed Tomography

Overview

A cardiac CT (computed tomography) is a scan that takes very detailed pictures of your heart and the blood vessels around it. It uses X-rays and a computer to build clear 3D images, a little like slicing a loaf into very thin slices and then putting it back together again. Doctors use it to look for narrowed or blocked heart arteries, to check the heart's structure, and to see how blood is flowing. There are two common types: a calcium score scan, which measures chalky calcium build-up in the heart arteries, and a CT coronary angiogram, which uses a dye to show the arteries clearly.

Yes. Cardiac CT is one of the most widely used heart tests in the world, and it is being used more and more often because it is quick, safe and can often save people from having more invasive tests.

Anyone can be offered a cardiac CT, but it is most often arranged for adults who have chest pain, unexplained breathlessness, or a higher-than-average chance of heart artery disease. It is also used to check people who have already had stents or heart surgery, and sometimes to help plan heart procedures.

Symptoms

Common symptoms

• Chest pain, tightness or pressure, especially during activity
• Breathlessness when walking, climbing stairs or exercising
• Unusual tiredness or low energy during normal activities
• A fluttering, pounding or racing feeling in the chest (palpitations)
• Dizziness or light-headedness with exertion
• Discomfort in the arm, shoulder, jaw, neck or back that comes on with activity

Symptoms in children

• Cardiac CT is rarely used in children. When it is, it is usually to look at a heart problem present from birth rather than narrowed arteries.
• In children, signs that may lead to heart tests include poor feeding, slow growth, bluish lips or skin, or getting very tired quickly when playing.
• Children's scans are planned carefully to keep the radiation dose as low as possible, and a parent or carer can usually stay nearby.

Symptoms in older adults

• Older adults are much more likely to be offered a cardiac CT, because heart and blood vessel changes become more common with age.
• Symptoms can be less obvious in older people — for example, breathlessness or tiredness rather than classic chest pain.
• If you have kidney problems, an irregular heartbeat or trouble holding your breath for a few seconds, tell the scan team in advance so they can plan around it.

Causes

Main causes

• Chest pain of unknown cause, where the doctor wants to rule narrowed heart arteries in or out
• Suspected coronary artery disease (narrowing of the vessels that supply blood to the heart muscle)
• Checking whether a stent or a bypass graft is still open and working
• Planning certain heart procedures, such as valve replacement, by mapping the heart's structure first
• Looking at problems present from birth in the heart's chambers or major vessels (congenital heart disease)
• Checking the sac around the heart or looking for other structural causes of breathlessness

Risk factors

• Smoking or having smoked in the past
• High blood pressure or high cholesterol
• Diabetes, or family history of early heart disease
• Being physically inactive, overweight, or having a diet high in salt and saturated fat
• Increasing age and being male, or being female after the menopause
• Kidney problems, which matter because the contrast dye is cleared by the kidneys
• A previous allergic reaction to contrast dye, or a history of asthma, which the scan team will want to know about

When to see a doctor

See a doctor urgently if:

• You have new chest pain, or chest pain that is getting more frequent, stronger or lasting longer
• You feel breathless at rest or with very little effort
• You have palpitations with dizziness, chest discomfort or near-fainting
• You develop a rash, itching, swelling or feeling of illness after a contrast dye scan

Book a routine appointment if:

• You have been offered a cardiac CT and want to talk through the benefits, risks and alternatives
• You are worried about a family history of heart disease and want to discuss your own risk
• You have questions about your results or what the findings mean for you
• You take regular medicines and want to know whether anything needs to change before the scan

Diagnosis

The cardiac CT is itself the test that gives your doctor the answer. You are usually referred by a GP or a heart specialist after a conversation about your symptoms, an examination, and often some simple first-line tests. The scan report describes whether your heart arteries are clear, mildly, moderately or severely narrowed, and whether anything else needs attention. Your doctor then explains what the pictures show and what, if anything, needs to happen next.

Tests that may be done

• A conversation about your symptoms, medical history, medicines and allergies
• Blood tests to check cholesterol, blood sugar and kidney function
• An ECG (a painless tracing of the heart's electrical rhythm)
• A calcium score scan — a very quick CT that measures calcium in the heart arteries without any dye
• A CT coronary angiogram — a CT scan with contrast dye that shows the arteries in detail
• Sometimes other tests such as an ultrasound of the heart, a stress test, or an invasive angiogram if more detail is needed

What to expect at your appointment

You may be asked not to eat for a few hours beforehand and to skip caffeine that day, because caffeine can make the heart beat faster. On arrival you may be given medicine to slow your heart rate so the pictures are sharp, and a small spray or tablet under the tongue to widen the heart arteries. You lie on a table, sticky patches are placed on your chest to track your heartbeat, and a small needle is put in your arm for the dye. You will be asked to hold your breath for a few seconds while the pictures are taken. The whole visit usually takes under an hour, and you can normally drive yourself home and eat and drink as usual afterwards.

Treatment

Treatment depends entirely on what the scan shows. If your heart arteries are clear or only mildly narrowed, you may not need any treatment beyond healthy habits and a follow-up chat. If narrowing is found, your doctor will discuss ways to protect your heart, which may include lifestyle changes, medicines, and sometimes a procedure to open a narrowed artery.

Self-care at home

• Stop smoking — this is the single biggest thing you can do for your heart, and support is available
• Eat a heart-healthy diet with plenty of vegetables, fruit, whole grains, beans, fish and nuts, and less salt and processed food
• Aim for regular activity such as brisk walking, building up gradually and checking with your doctor first if you have symptoms
• Keep to a healthy weight and limit alcohol
• Take any prescribed medicines as directed and keep up with follow-up appointments
• Drink plenty of water after a contrast scan unless your doctor has told you to limit fluids

Medical treatments

If the scan shows narrowed heart arteries, doctors usually suggest a combination of approaches rather than one single fix. These can include medicines to lower cholesterol and blood pressure, medicines to reduce the heart's workload and protect the arteries, and help with smoking, diet and activity. Your doctor will explain why each one is suggested, what it does, and how long you are likely to need it — always ask your pharmacist or doctor if you are unsure about anything you have been given.

When is surgery considered?

Most people who have a cardiac CT never need surgery. If the scan shows a severe narrowing and your symptoms or risk are significant, your heart team may discuss a procedure to open the artery with a small balloon and a mesh tube (stent), or a bypass operation. These are offered only after a full discussion of benefits and risks, and often after further tests.

Living with this condition

Most people go back to normal the same day. You can eat, drink and take your usual medicines unless told otherwise, and there is no wound to look after. If you had contrast dye, drink extra water for the rest of the day to help your kidneys clear it. You may feel a little tired afterwards, and some people get a mild headache from the medicine used to slow the heart rate — this usually settles quickly.

Lifestyle tips

• Build heart-healthy habits gradually rather than all at once, so they stick
• Keep a simple record of any symptoms and bring it to your next appointment
• Know your numbers — blood pressure, cholesterol and blood sugar — and ask what they mean for you
• Ask for help to stop smoking; combining support and medication works better than willpower alone
• Keep active within what feels comfortable, and stop and rest if you get chest pain or breathlessness

Diet and exercise

A heart-friendly way of eating means more vegetables, fruit, whole grains, beans, lentils, nuts and oily fish, and less salt, sugar and heavily processed food. For activity, aim for something you enjoy most days — a brisk walk, cycling, swimming or dancing — starting with short sessions and building up. If activity brings on chest pain or breathlessness, stop, rest, and tell your doctor before pushing further.

Mental health and emotional wellbeing

Being sent for a heart scan can be worrying, and waiting for results often feels like the hardest part. Feeling anxious, distracted or sleepless is very common and completely understandable. It often helps to talk to someone — a partner, friend, GP or a trained counsellor — and to write down your questions before appointments so nothing gets forgotten. If low mood or anxiety is lasting more than a couple of weeks or affecting daily life, please reach out for support.

Prevention

The scan itself is a test, not an illness, so it cannot be prevented — and it is usually nothing to worry about. What you can influence is your heart risk, and the same healthy habits protect your heart whether or not you ever need a scan.

Screening programmes

There is no routine screening programme for heart artery disease using cardiac CT for everyone. Some doctors use a calcium score scan for certain adults at higher risk, and your GP can advise whether that applies to you. If you have a strong family history of early heart disease, or you have diabetes or high blood pressure, ask about your heart risk at your next check-up.

Complications

If left untreated

• If narrowed heart arteries are present and not addressed, the risk of a heart attack or heart failure over time is higher
• Narrowing can slowly reduce how much blood reaches the heart muscle, causing breathlessness and tiredness with everyday activity
• Rarely, the contrast dye can affect kidney function, especially in people who already have kidney problems — which is why your kidney function is checked first
• Rarely, a reaction to the contrast dye can occur, ranging from a mild rash to a more serious reaction; the scan team is trained to spot and treat this quickly

Long-term outlook

The outlook is generally very good. A cardiac CT gives you and your doctor clear information, often at a stage when changes can still be managed well with lifestyle and medicines. Many people are reassured that their arteries are normal or only mildly changed and need no further tests. Even when narrowing is found, modern care is effective and most people go on to live full, active lives.

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