Atrial Appendage Occlusion Devices

What is a WATCHMAN device?

The majority of patients who have a stroke related atrial fibrillation do so because they get a blood clot that forms in the left atrial appendage.  The left atrial appendage is a small sac that is attached to the left atrium and has no practical function from a heart performance point of view.  Unfortunately as it is a blind ended sac blood enters it and if the heart is in atrial fibrillation blood is more prone to clot when in the appendage.  If the clot then dislodges and then goes to the brain it can cause a stroke.  Warfarin and other blood thinners are designed to keep the blood thinned so it does not clot.  In cases where patients cannot take blood thinners a WATCHMAN device can be used to “plug off” the appendage so that blood cannot enter.  It is a one off procedure and once the WATCHMAN is implanted it is in for life.


From consultation through to treatment you will receive professional care throughout.


Take a look at Davids profile on iWantGreatCare and see what others have said about his work.


David is one of the UK’s most active doctors in the field, performing an impressive volume of procedures each year.

Still have some questions?

If you still have some unanswered questions or a general query about this specific condition please get in contact and we can give you anymore information you require.


The procedure is performed under general anaesthetic (ie; you will be put to sleep by an anaesthetist). From the top of the right let cardiologists access the left atrium in a similar fashion to how a patient would have an atrial fibrillation ablation. Whilst the patient is asleep a small camera is passed down the gullet and the heart is viewed on a screen using a TOE (a transesophageal echo). Using a combination of the TOE imaging and the X-ray images the WATCHMAN implant is placed into the appendage to plug off the entry of blood into the appendage. The whole process typically takes between 45 minutes and 2 hours. Patients are often kept in overnight and then are reviewed a few weeks down the line to have a further TOE to ensure that the WATCHMAN is fully sealed. If at that point all looks well any of the anticoagulants that the patients are taking can be discontinued and they will have on-going protection with the WATCHMAN device that is in situ.

No. Patients must have non-valvular atrial fibrillation and we do not recommend WATCHMAN in patients who don’t simply want to take anticoagulants. We generally reserve WATCHMAN implants for patients who for the reasons described above are unable to take anticoagulants safely in the long term.

Like any invasive cardiology procedure there are risks. There is a small risk of damaging the blood vessel at the top of the leg. There is a small risk that WATCHMAN devices can become dislodged when the implant is performed and a surgical team will be required to open a patient’s chest and remove the WATCHMAN implant if it is dislodged. There are also small risks of stroke and perforation of the heart (pericardial effusion/tamponade) during the procedure. Overall the total risk of the procedure is around 2-3% of a complication. Once the device is placed and it is firmly in situ and you recover from the anaesthetic the main risk of a complication has passed.

You are generally discharged home the following day after a heart scan. We often send patient home on some form of blood thinner or anti-platelets with a view to stopping it as soon as we can at follow up.

We then bring you back for a special heart scan called a trans-oesphageal echo (TOE) after approximately 6 weeks to check the WATCHMAN is fully sealed. Usually at that stage we try and get patients off all/most of their blood thinning medication but often they may still need something such as aspirin.

Dr Fox is one of the few doctors in the UK trained to successfully implant WATCHMAN devices in atrial fibrillation patients.

Many patients who have atrial fibrillation require blood thinning treatments (anticoagulants) such as warfarin or the newer drugs such as Rivaroxaban, Apixaban or Dabigatran.

Unfortunately there are a sub-group of patients who require blood thinning treatment but are unable to take them. These patients have usually had a significant bleed in the past which means that although they need blood thinners to reduce the risk of stroke related to their atrial fibrillation they cannot take them safely.

Examples of such patients include patients who have suffered an intracerebral bleed (a bleed in the brain) and in whom specialist neurologists or neurosurgeons have indicated that it is no longer safe for them to take anticoagulants. Other examples of patients who need blood thinning medication but cannot take it include those who lose blood from their bowel slowly (such as angiodysplasia of the colon) in whom long term blood thinning medication is not safe.

Unfortunately many of these patients simply have their blood thinners stopped and their protection against clots forming in the heart is then no longer being provided.

WATCHMAN device blocking off the left atrial appendage to prevent clot formation and reduce the risk of stroke

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