Electrocardiography
Cardiac diagnostic tests help check the electrical activity and rhythm of your heart. Some tests, such as an ECG, record your heart's activity at one moment. Others, such as Holter monitors or longer term cardiac monitors, track your heart rhythm over several days. There also are tests, such as the exercise tolerance test, also called the stress ECG, which show how your heart behaves when you are active. These tests help identify irregular heartbeats and how your heart responds during daily life and exercise.
Electrocardiogram
The ECG is a quick and painless test that records the electrical signals your heart produces. Test results can help diagnose heart attacks and irregular heartbeats, called arrhythmias.
What does the ECG test show?
It shows how fast your heart is beating, whether the rhythm is regular, and if there are any signs of strain or electrical changes.
How do I prepare for the ECG?
No special preparation is needed. Try not to use creams or lotions on your chest on the day of the test, as they can make the stickers that hold the electrodes to your body fall off.
What happens during the ECG?
You lie down while a clinician places stickers on your chest, arms and legs. You simply relax and breathe normally while the machine records your heart for a few seconds.
How long does the ECG take?
The recording takes only a few minutes. The whole appointment is usually very quick.
What happens after the ECG?
You can return to your usual activities straightaway. A clinician looks at your heart signal patterns and explains the results.
Holter monitor
A Holter monitor is a small device you wear at home for up to seven days. It uses five to 12 small electrodes, which are sensors. The electrodes are placed around your chest to record your heart from different angles. The monitor tracks every heartbeat while you go about your day, to give your doctor clear information about how your heart is working.
When to use a Holter monitor vs. cardiac patch monitor
A Holter monitor usually is used when symptoms happen every day and your doctor needs results quickly. The monitor can be a bit uncomfortable because of the wires from the electrodes.
A cardiac patch monitor is more suitable when symptoms are less frequent or unpredictable. It's a small patch worn on the chest for up to 14 days. The size of the patch makes it more comfortable. The longer monitoring period gives it a higher diagnostic yield, meaning it's more likely to pick up irregular heart rhythms that don't occur every day.
What does the Holter monitor test show?
A Holter monitor test shows how your heart beats during your everyday activities — while you walk, work, sleep and rest. It records every heartbeat for up to seven days, which helps your doctor spot irregular rhythms, pauses, or fast and slow heart rates that might not appear during a short ECG. A Holter monitor also can show how your heart responds to stress, movement and medications.
How do I prepare for the Holter monitor test?
Wear loose, comfortable clothing. Avoid lotions on your chest so the stickers that hold the electrodes to your body stay in place. You can continue most of your usual activities unless advised otherwise.
What happens during the Holter monitor test?
A clinician places stickers on your chest and connects them to the small monitor, which can be worn on a belt or around your neck like a necklace. You then go home and carry on with your usual routine while the device records your heart rhythm. You'll also be asked to keep a simple diary of your symptoms, such as palpitations, dizziness, chest discomfort or shortness of breath, and note the time they occur. This allows your doctor to match your symptoms with what the Holter monitor recorded at that exact moment, giving a clearer picture of what might be causing your symptoms.
How long does the Holter monitor test take?
It varies depending on your exact condition. You might need to wear the monitor for 1 to 7 days.
What happens after the Holter monitor test?
You return the device to the clinic. Your recordings are downloaded and reviewed by a clinician.
Cardiac monitor
A cardiac monitor is a lightweight device that you wear on your chest for several days. It records your heart rhythm for longer periods than a Holter monitor does. It checks your heartbeat all day and night for up to 14 days to look for any irregular rhythms. Because it stays on longer than a traditional Holter monitor, it has a higher diagnostic yield. This means it's more likely to catch heart rhythm problems that don't happen every day.
What does the cardiac monitor test show?
The cardiac monitor helps detect irregular heart rhythms that happen less often and may not appear on shorter tests. Longer monitoring increases the chance of finding the cause of symptoms, such as palpitations or dizziness.
How do I prepare for the cardiac monitor test?
Wear comfortable clothing and avoid creams or lotions on your chest. You can continue most daily activities while wearing the monitor.
What happens during the cardiac monitor test?
A clinician attaches the monitor to your chest. You then go home and continue your usual routine while the device records your heart rhythm during the day and night. You’ll also keep a simple diary of any symptoms you feel, such as palpitations, dizziness, chest discomfort or shortness of breath, and note the time they happen. This helps your doctor match your symptoms with what the monitor recorded at that exact moment, giving a clearer picture of what might be causing your symptoms.
How long does the cardiac monitor test take?
You wear the monitor for 72 hours, seven days or 14 days, depending on what your clinician recommends.
What happens after the cardiac monitor test?
You return the monitor to the clinic. Your team will analyse the recordings and prepare a report.
Exercise tolerance test
Also known as a stress ECG, an exercise tolerance test (ETT) checks how your heart works when your body is active. To do this, you walk on a treadmill while your heart rhythm is recorded.
What does the ETT show?
The ETT checks how your heart responds when you walk on a treadmill. It can show if there are issues with the blood supply to your heart and whether your heart rhythm and blood pressure behave as they should during exercise. If the ETT shows irregular parameters, your doctor may suggest further tests to rule out coronary artery disease or to look more closely at how your heart works under stress. Sometimes the consultant recommends additional heart imaging, such as a CT coronary angiogram or a stress cardiac MRI.
How do I prepare for the ETT?
Wear comfortable clothes and shoes. Avoid heavy meals and caffeine beforehand, unless your clinician gives different instructions.
What happens during the ETT?
A clinician places stickers on your chest to record your heart rhythm. You walk on a treadmill that gradually becomes faster and steeper. Your heart rate, blood pressure and symptoms are monitored throughout.
You may feel warm or a little out of breath. The team supports you throughout the test and can stop the test at any time if needed.
How long does the ETT take?
The full appointment usually takes 30 to 45 minutes, including preparation and a short recovery period.
What happens after the ETT?
You can rest briefly and then return to your usual activities. A clinician reviews your results and explains what they mean. A cardiologist also looks at the findings and advises whether you need lifestyle changes, medication or further heart tests.
Book an appointment
If you need an accurate mammogram with quick results, request an appointment at Mayo Clinic Healthcare in London online or call us at +44 (0) 207 871 2575.