Atrial Fibrillation (AF)RESPOND-AFNCT06922695
Responding to AF: Pill-in-Pocket Anticoagulation Guided by Automated Monitoring and Alerts
A study testing Pill-in-pocket anticoagulation in people with Atrial Fibrillation (AF) and Atrial Fibrillation (Prevention of Stroke), run by Oxford University Hospitals NHS Trust at 1 site in United Kingdom.
Trial summary
Atrial Fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting 1-2 million people in the UK. AF is characterised by uncoordinated electrical activation and ineffective contraction of the upper cardiac chambers. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Atrial Fibrillation (AF), Atrial Fibrillation (Prevention of Stroke)
- What is being tested?
- Pill-in-pocket anticoagulation
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 50 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 14 Apr 2025to 31 Jul 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Participant is willing and able to give informed consent for participation in the trial.
- Understand the risk and willing to discontinue oral anticoagulation (OAC).
- Any gender aged 18 years or above.
- Non-valvular paroxysmal atrial or persistent atrial fibrillation (AF) with a current rhythm control strategy. Paroxysmal patients must have < 3 documented or symptomatic episodes of >1 hour duration in the previous 3 months. Persistent patients must have been in continuous sinus rhythm for at least 4 weeks prior to enrolment.
- CHA2DS2-VASc score between 1 and 3 in men and between 2 and 4 in women.
- Able to take direct-acting oral anticoagulant (DOAC) in guideline recommended doses.
- Left atrial (LA) diameter on echocardiogram less than 5 cm (anteroposterior dimensions) or LA volume less than 48 ml/m2.
Who cannot join
- Any contraindication to OAC therapy with a DOAC in guideline recommended doses.
- Mechanical heart valve prosthesis or moderate-to-severe mitral valve stenosis.
- Permanent atrial fibrillation.
- Hypertrophic cardiomyopathy.
- Documented previous thromboembolic event (stroke, transient ischaemic attack or systemic embolism).
- Spontaneous echo contrast observed in any imaging modality.
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- History of intracardiac thrombi.
- History of congenital heart disease.
- Severe chronic renal disease (eGFR <15 ml/m) or on renal replacement therapy.
- Pregnant or planning pregnancy.
- Indication for OAC other than atrial fibrillation.
- Inability to comply with protocol.
- Smartphone with operating system (OS) not compatible with MyCareLink Heart app.
- Contraindication for implantable cardiac monitor.
- Visual or physical impairment that prevents ability to read and acknowledge smartphone/watch notifications.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Oxford University Hospitals NHS Trust, John Radcliffe Hospital
Oxford, Oxfordshire, OX3 9DU
About this study
Official title: Pill-in-Pocket Oral Anticoagulation Responding to Atrial Fibrillation Episodes Guided by Continuous Rhythm Monitoring and Automated Smartphone Alerts
Atrial Fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting 1-2 million people in the UK. AF is characterised by uncoordinated electrical activation and ineffective contraction of the upper cardiac chambers. AF can occur in temporary episodes, as in paroxysmal AF, or can be sustained continuously beyond 7 days' duration, as in persistent AF.
The most significant potential complication of AF is stroke caused by a blood clot (thromboembolic stroke). If untreated, the risk of stroke in AF can be increased as much as five-fold, depending on the presence of other risk factors.
Read more
The mechanism of thromboembolic stroke in AF patients is complicated and understanding of factors involved remains incomplete. AF has been shown to disrupt normal bodily mechanisms for controlling bleeding and clotting (haemostasis) and normal blood flow inside the cardiac chambers. In disrupting these mechanisms, AF can be said to create a 'prothrombotic' state or environment within the blood and heart (a tendency to form clots) which can lead to blood clot formation and subsequently to stroke.
There is research evidence that AF-related stroke risk is not fixed and changes over time. This dynamic risk may be related to the episodic nature of AF, with stroke risk changing during an episode of AF and for a period of weeks after the episode terminates.
Analytic studies have shown that the risk of stroke is highest in the days after an AF episode has occurred, peaking at 5 days and returning to baseline by 30 days. Other studies have shown that the duration of the AF episode can also influence the risk of stroke following each episode, with longer episodes being higher risk.
This dynamic risk likely relates to changes in the activation of the body's blood-clotting system and changes in blood flow within the heart.
Current clinical guidelines recommend that patients with AF and risk factors for stroke are treated with daily, uninterrupted anticoagulation (blood-thinning medication) to reduce the risk of stroke. These guidelines do not take into account the temporal pattern of AF or the frequency or duration of AF episodes.
An emerging approach to anticoagulation in AF is pill-in-pocket oral anticoagulation (PIPOAC). In this approach, AF patients only take their anticoagulation in response to episodes of AF, and for a period of time after normal heart rhythm is restored. This approach may suit AF patients who have lower risk, lower frequency AF and who wish to reduce their exposure to anticoagulation medication. It may also suit AF patients who have higher bleeding risk related to anticoagulation.
The RESPOND-AF study proposes a novel approach to delivering PIPOAC. It is a pilot study of this novel approach recruiting 50 participants. This includes participants having continuous heart rhythm monitoring using the Medtronic LINQ II implantable cardiac monitor. The LINQ II continuously monitors for evidence of AF. If AF is detected a transmission is uploaded to the Medtronic Carelink cloud portal.
Traditionally, healthcare professionals need to sign in to this portal to check for any transmissions. For the purposes of PIPOAC this traditional approach would be too slow and create a burdensome workload for clinicians. Due to the properties of blood clot formation in AF, it is important to initiate oral anticoagulation within 48 hours of AF episode onset to disrupt the clot-formation process.
For the purposes of this study, the investigators have developed a custom-designed software which continuously screens for transmissions of AF on the Carelink cloud portal. When an AF episode has been detected by the LINQ II monitor, the software will send an SMS smartphone alert to the patient informing them of the AF episode and instructing them to commence their oral anticoagulation as soon as possible. This approach, if shown to be safe and effective and acceptable to patients, could open the path to wider use of Pill-in-pocket oral anticoagulation.
This novel treatment can reduce the need for anticoagulation, meaning fewer bleeding complications. Pill-in-pocket oral anticoagulation empowers patients by offering a new treatment choice beyond current limited options.
- Being tested
- Pill-in-pocket anticoagulation
- Keywords
- Atrial Fibrillation, Pill-in-pocket anticoagulation, Anticoagulation, As-required anticoagulation, Intermittent anticoagulation
- Medical subject headings
- Atrial Fibrillation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Pill-in-pocket anticoagulationOther
Also called As-required anticoagulation, Intermittent anticoagulation
Participants will stop their oral anticoagulation after a 30-day period free of AF episodes. After this, they will only take their anticoagulation in response to an episode of AF detected by their implantable cardiac monitor. The participants will receive an automated smartphone alert instructing them to commence their anticoagulation as soon as AF is detected.
| Study group | Role | What they receive |
|---|---|---|
| Pill-in-pocket anticoagulation | Experimental | Participants will stop their oral anticoagulation after a 30-day period free of AF episodes. After this, they will only take their anticoagulation in response to an episode of AF detected by their implantable cardiac monitor. The participants will receive an automated smartphone alert instructing them to commence their anticoagulation as soon as AF is detected. Receives: Other: Pill-in-pocket anticoagulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
To investigate the reduction in oral anticoagulation (OAC) utilisation during follow-up.
Calculate the proportion of time off anticoagulation OAC
Measured: During follow-up (minimum 13 months)
Secondary outcomes (7)
Thromboembolic events (Ischaemic stroke, transient ischaemic attack (TIA) and systemic embolism)
Calculate the rate of ischaemic stroke, TIA and systemic embolism in patients on as-required OAC
Measured: During follow-up (minimum 13 months)
Major bleeding
Calculate the rate of major bleeding in patients on as-required OAC
Measured: During follow-up (minimum 13 months)
Minor bleeding
Calculate the rate of minor bleeding in patients on as-required OAC
Measured: During follow-up (minimum 13 months)
Any stroke (ischaemic, haemorrhagic or undetermined)
Calculate the stroke rate (ischaemic, haemorrhagic or undetermined)
Measured: During follow-up (minimum 13 months)
All-cause mortality
Calculate the rate of all-cause mortality in patients on as-required OAC
Measured: During follow-up (minimum 13 months)
Protocol adherence
Calculate the number of daily transmissions and percentage of patients that restarts OAC within 24 hours of the smartphone-alert.
Measured: During follow-up (minimum 13 months)
To assess response time from AF episode onset to patient starting as-required OAC
Time from AF episode onset to detection, time to alerts being sent and acknowledged and OAC
Measured: During follow-up (minimum 13 months)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Apr 2025
- Study start14 Apr 2025
- Primary completion30 Apr 2027 (estimated)
- Study completion31 Jul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Atrial Fibrillation (AF)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Oxford University Hospitals NHS Trust
- Sponsor type
- University, hospital or other
- Collaborators
- Medtronic
- Responsible party
- Principal investigator, Tim Betts MD MBChB FRCP, Oxford University Hospitals NHS Trust
- Investigators
- Prof Tim R. Betts MD MBChB FRCP, Principal investigator, University of Oxford
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06922695
- Sponsor's protocol ID
- 17913
- Other IDs
- IRAS ID 329237, CPMS 56479, 24/WS/0126
- Acronym
- RESPOND-AF
- Status last verified
- Aug 2026
- First submitted
- 3 Apr 2025
- Last updated
- 12 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Not included in Informed Consent Form.
Study at a glance
From the registry record, last updated by the sponsor on 12 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pill-in-Pocket Oral Anticoagulation Responding to Atrial Fibrillation Episodes Guided by Continuous Rhythm Monitoring and Automated Smartphone Alerts
- ClinicalTrials.gov ID
- NCT06922695
- Acronym / sponsor ID
- RESPOND-AF / 17913
- Keywords
- Atrial Fibrillation, Pill-in-pocket anticoagulation, Anticoagulation, As-required anticoagulation, Intermittent anticoagulation
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Oxford University Hospitals NHS TrustUniversity, hospital or other
- Collaborators
- Medtronic
- Study start
- 14 Apr 2025 (actual)
- Primary completion
- 30 Apr 2027 (estimated)
- Study completion
- 31 Jul 2027 (estimated)
- First posted
- 10 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Atrial Fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting 1-2 million people in the UK. AF is characterised by uncoordinated electrical activation and ineffective contraction of the upper cardiac chambers. AF can occur in temporary episodes, as in paroxysmal AF, or can be sustained continuously beyond 7 days' duration, as in persistent AF.
The most significant potential complication of AF is stroke caused by a blood clot (thromboembolic stroke). If untreated, the risk of stroke in AF can be increased as much as five-fold, depending on the presence of other risk factors.
The mechanism of thromboembolic stroke in AF patients is complicated and understanding of factors involved remains incomplete. AF has been shown to disrupt normal bodily mechanisms for controlling bleeding and clotting (haemostasis) and normal blood flow inside the cardiac chambers. In disrupting these mechanisms, AF can be said to create a 'prothrombotic' state or environment within the blood and heart (a tendency to form clots) which can lead to blood clot formation and subsequently to stroke.
There is research evidence that AF-related stroke risk is not fixed and changes over time. This dynamic risk may be related to the episodic nature of AF, with stroke risk changing during an episode of AF and for a period of weeks after the episode terminates.
Analytic studies have shown that the risk of stroke is highest in the days after an AF episode has occurred, peaking at 5 days and returning to baseline by 30 days. Other studies have shown that the duration of the AF episode can also influence the risk of stroke following each episode, with longer episodes being higher risk.
This dynamic risk likely relates to changes in the activation of the body's blood-clotting system and changes in blood flow within the heart.
Current clinical guidelines recommend that patients with AF and risk factors for stroke are treated with daily, uninterrupted anticoagulation (blood-thinning medication) to reduce the risk of stroke. These guidelines do not take into account the temporal pattern of AF or the frequency or duration of AF episodes.
An emerging approach to anticoagulation in AF is pill-in-pocket oral anticoagulation (PIPOAC). In this approach, AF patients only take their anticoagulation in response to episodes of AF, and for a period of time after normal heart rhythm is restored. This approach may suit AF patients who have lower risk, lower frequency AF and who wish to reduce their exposure to anticoagulation medication. It may also suit AF patients who have higher bleeding risk related to anticoagulation.
The RESPOND-AF study proposes a novel approach to delivering PIPOAC. It is a pilot study of this novel approach recruiting 50 participants. This includes participants having continuous heart rhythm monitoring using the Medtronic LINQ II implantable cardiac monitor. The LINQ II continuously monitors for evidence of AF. If AF is detected a transmission is uploaded to the Medtronic Carelink cloud portal.
Traditionally, healthcare professionals need to sign in to this portal to check for any transmissions. For the purposes of PIPOAC this traditional approach would be too slow and create a burdensome workload for clinicians. Due to the properties of blood clot formation in AF, it is important to initiate oral anticoagulation within 48 hours of AF episode onset to disrupt the clot-formation process.
For the purposes of this study, the investigators have developed a custom-designed software which continuously screens for transmissions of AF on the Carelink cloud portal. When an AF episode has been detected by the LINQ II monitor, the software will send an SMS smartphone alert to the patient informing them of the AF episode and instructing them to commence their oral anticoagulation as soon as possible. This approach, if shown to be safe and effective and acceptable to patients, could open the path to wider use of Pill-in-pocket oral anticoagulation.
This novel treatment can reduce the need for anticoagulation, meaning fewer bleeding complications. Pill-in-pocket oral anticoagulation empowers patients by offering a new treatment choice beyond current limited options.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Pill-in-pocket anticoagulation | Experimental | Other: Pill-in-pocket anticoagulationParticipants will stop their oral anticoagulation after a 30-day period free of AF episodes. After this, they will only take their anticoagulation in response to an episode of AF detected by their implantable cardiac monitor. The participants will receive an automated smartphone alert instructing them to commence their anticoagulation as soon as AF is detected. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Participant is willing and able to give informed consent for participation in the trial.
- Understand the risk and willing to discontinue oral anticoagulation (OAC).
- Any gender aged 18 years or above.
- Non-valvular paroxysmal atrial or persistent atrial fibrillation (AF) with a current rhythm control strategy. Paroxysmal patients must have < 3 documented or symptomatic episodes of >1 hour duration in the previous 3 months. Persistent patients must have been in continuous sinus rhythm for at least 4 weeks prior to enrolment.
- CHA2DS2-VASc score between 1 and 3 in men and between 2 and 4 in women.
Key exclusion criteria (15 listed)
- Any contraindication to OAC therapy with a DOAC in guideline recommended doses.
- Mechanical heart valve prosthesis or moderate-to-severe mitral valve stenosis.
- Permanent atrial fibrillation.
- Hypertrophic cardiomyopathy.
- Documented previous thromboembolic event (stroke, transient ischaemic attack or systemic embolism).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Pill-in-pocket anticoagulationAlso: As-required anticoagulation, Intermittent anticoagulationParticipants will stop their oral anticoagulation after a 30-day period free of AF episodes. After this, they will only take their anticoagulation in response to an episode of AF detected by their implantable cardiac monitor. The participants will receive an automated smartphone alert instructing them to commence their anticoagulation as soon as AF is detected. | Other | Pill-in-pocket anticoagulation |
Primary outcome
To investigate the reduction in oral anticoagulation (OAC) utilisation during follow-up.
Time frame: During follow-up (minimum 13 months)
Calculate the proportion of time off anticoagulation OAC
7 secondary outcomes
Thromboembolic events (Ischaemic stroke, transient ischaemic attack (TIA) and systemic embolism)
Time frame: During follow-up (minimum 13 months)
Major bleeding
Time frame: During follow-up (minimum 13 months)
Minor bleeding
Time frame: During follow-up (minimum 13 months)
Any stroke (ischaemic, haemorrhagic or undetermined)
Time frame: During follow-up (minimum 13 months)
All-cause mortality
Time frame: During follow-up (minimum 13 months)
Protocol adherence
Time frame: During follow-up (minimum 13 months)
To assess response time from AF episode onset to patient starting as-required OAC
Time frame: During follow-up (minimum 13 months)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Aug 2026.
- Individual participant dataSharing planned: No. Not included in Informed Consent Form.
Related trials for Atrial Fibrillation (AF)
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Horizon 360 Protocol for the Treatment of Paroxysmal Atrial Fibrillation With the Sphere-360™ Catheter and Affera™ Mapping and Ablation System (Horizon 360)
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CONVERGE Post-Approval Study (PAS)
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Hummingbird ICE Study
ATRIAL APPENDAGE CLOSURE for ATRIAL FIBRILLATION, Atrial Fibrillation (AF)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Prof Tim R. Betts MD MBChB FRCP principal investigator
University of Oxford
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Pill-in-pocket anticoagulation in people with Atrial Fibrillation (AF) and Atrial Fibrillation (Prevention of Stroke), run by Oxford University Hospitals NHS Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 12 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To investigate the reduction in oral anticoagulation (OAC) utilisation during follow-up. (time frame: During follow-up (minimum 13 months)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Aug 2026.