What does it mean to take part?

All patients willing to take part in the study will be asked to sign an informed consent form. You will also be asked if you want to take part in two optional extra parts of the study, the Echocardiogram (heart scan) sub-study and the AF Burden (rhythm monitoring) sub-study.

Screening and consent (all patients)

Prior to beginning treatment, you will have some investigations to check that you are suitable for the study. Some of these will be done as part of normal care but some will be extra tests that are required for the study. Sometimes some of the tests need to be repeated if they are outside the timescale for the study. These tests and assessments may include:

• Asking about your medical history and current medications

• Height and weight

• Electrocardiogram (ECG) – a heart tracing

• Echocardiogram (heart ultrasound scan) – a heart scan where jelly is placed on the skin above your heart and a probe used to see the heart (very similar to a scan of a baby in pregnant women)

• Blood test to check kidney function, heart function, red blood cells and blood sugar level (this blood test will be part of your routine care; the information required for the trial will be collected from your medical records).

You will also be asked to complete some questionnaires either through an app on your phone or on paper according to your preference.

You will be assessed to ensure that you meet all the criteria for the study. These assessments will provide us with baseline information which will be used (alongside other information we collect throughout the study) to assess which treatment has better outcomes for patients.

If it is confirmed that you are able to take part in the study, you will be placed in one of 2 groups: medical treatment alone or medical treatment with catheter ablation. This is a process called randomisation. This means that neither you nor your doctor will be able to decide which treatment you will have. Trials are often randomised because if the researchers or doctors were to decide who should get which treatment, they might be influenced by what they know about their patients. Having randomisation allows us to be sure that results are reliable and that a fair comparison between the treatment groups can be carried out.

Medical treatment alone group:

Patients randomised to take part in the medical treatment alone group will receive the best tablet therapy for heart failure that is available. This will be managed by your local heart failure specialist team.

Medical treatment and catheter ablation group:

Patients randomised to take part in the medical treatment and catheter ablation group will receive the best tablet therapy for heart failure that is available. This will be managed by your local heart failure specialist team. Patients will also be booked to undergo a catheter ablation. Before the catheter ablation, you will be prepared for the procedure which involves lying on an X-ray table. You will be given deep sedation or a general anaesthetic, and small tubes will be placed at the blood vessel at the top of your leg by a cardiologist. The catheter ablation procedure will be carried out using standard approaches by your cardiologist either with freezing or heating or electrically treating the veins around the heart. The cardiology team will perform the catheter ablation as they usually do in your hospital. Some people will still have atrial fibrillation after the first ablation, and you may be offered another ablation if this happens.

Follow Up (all participants):

In order to collect data for the trial, we will ask you to complete some questionnaires either through the Fibricheck app on your phone or on paper, according to your preference. You will be asked to do this when you enter the study and at 6 months and 12 months after you entered the study.

If you have signed up to the Echocardiogram sub-study, you will be asked to come into hospital for an echocardiogram (heart ultrasound scan) at 12 months.

If you have signed up to take part in the AF Burden sub-study you will be asked to record your pulse at least once a day for 7 days on the Fibricheck app on your phone at home. You will be asked to do this at 6 months and 12 months after entering the study. You can also use the app to record your pulse at any time you like up to 12 months if you wish to.

We will continue to monitor you through your usual (electronic) health record in the NHS.

Long Term Follow Up (all patients):

During the study and for your lifetime, information about your health status and any hospitalisations you have had will be collected from centralised electronic NHS databases. This is called “data linkage”. You will not be asked to do anything at these time points.

We would like your consent to continue to collect this data for use in this study and future research projects. You will not be asked to anything at these time points.