AuthorisedTherapeutic confirmatory (Phase III)Interventional

Colchicine after Electrocardioversion for Atrial Fibrillation - The COLECTRO-AF Trial

Atrial fibrillation is a common heart condition that causes an irregular and often fast heartbeat. A common treatment is electrical cardioversion, which gives the heart a brief electrical pulse to reset it back into a normal rhythm. However, it is very common for the irregular rhythm to come back over time. This Phase 3 clinical trial is testing whether a low-dose tablet called colchicine can prevent the irregular rhythm from returning. Colchicine is a medicine usually used to reduce swelling and inflammation in conditions like gout. In this study, half of the participants will take a 0.5 mg colchicine tablet once a day, and the other half will take an identical dummy tablet (placebo). Doctors will follow all participants for six months to see which group has fewer episodes of atrial fibrillation and fewer hospital visits.

At a glance

Status

Authorised

Phase

Therapeutic confirmatory (Phase III)

Sponsor

Universitaetsspital Basel

Enrolment target

100

Start

26 Jun 2026

Atrial Fibrillation

What is this study about?

Atrial fibrillation is a condition that makes the heart beat irregularly and sometimes too quickly. Many people have a hospital procedure called electrical cardioversion to treat it. During this quick procedure, doctors give the heart a small, controlled electrical shock while you are asleep to reset it back into a normal rhythm. While this often works well at first, the irregular rhythm unfortunately returns for many people within a few weeks or months.

Doctors believe that inflammation (swelling and irritation) in the heart muscle may play a key role in why atrial fibrillation comes back. In this trial, researchers are testing whether an anti-inflammatory medicine called colchicine can help. Colchicine has been safely used for many years to treat other inflammatory conditions, such as gout and pericarditis (inflammation around the heart).

The trial aims to see if taking a small daily dose of colchicine can protect the heart muscle and keep it beating steadily. By calming down inflammation after the cardioversion procedure, the medicine may reduce the chance of the irregular rhythm returning.

If the study shows positive results, it could lead to a simple, low-cost way to help people with atrial fibrillation stay in a normal rhythm for longer. This could mean fewer repeat hospital procedures, less need for stronger heart medications, and a better quality of life for patients.

Key takeaways

Tests whether the anti-inflammatory tablet colchicine keeps the heart in a normal rhythm after cardioversion.
Compares a daily 0.5 mg colchicine tablet against a dummy tablet (placebo).
Open to adults aged 18 and over who have atrial fibrillation and are having an electrical cardioversion.
Follow-up lasts for six months with clinic visits and regular heart rhythm checks (ECGs).
Taking part is entirely voluntary and does not replace your standard heart care.

Who may be eligible?

This trial is open to adults aged 18 and older who have been diagnosed with atrial fibrillation and are scheduled to have, or have just had, an electrical cardioversion procedure to reset their heart rhythm. Both men and women are welcome to take part.

To join, you must be well enough to take a daily tablet and willing to attend follow-up check-ups over a six-month period.

You might not be able to join if you have severe kidney or liver problems, if you take certain medicines that interact with colchicine, or if you are pregnant or breastfeeding. Your cardiology team will check your full medical history to confirm whether this trial is safe and suitable for you.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you aged 18 or older?
Have you been diagnosed with atrial fibrillation?
Are you having or have you recently had an electrical cardioversion?
Are you able to swallow a daily tablet for six months?
Are you willing and able to attend follow-up hospital visits for six months?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you will be randomly placed into one of two groups by a computer. One group will take a low-dose colchicine tablet (0.5 mg) once a day, while the other group will take an identical-looking dummy tablet (placebo). Neither you nor your study doctor will know which tablet you are receiving. You will take this tablet every day for six months.

During the trial, you will attend regular hospital check-ups, usually at one month, three months, and six months after your cardioversion. At these visits, the team will check your overall health, record your heart rhythm using an electrocardiogram (ECG), and ask if you have noticed any symptoms like palpitations. You may also receive phone calls between visits to see how you are feeling.

Your total involvement in the study will last about six months. You will continue to receive all of your usual heart care throughout.

Potential risks and benefits

Taking part may help keep your heart in a normal rhythm for longer, although this cannot be guaranteed because you might receive the dummy tablet. However, the regular monitoring you receive will give you close oversight of your heart health, and your participation will help doctors improve care for future patients. Colchicine can sometimes cause mild side effects, most commonly tummy upset, loose stools, or mild nausea. Taking part is completely voluntary. You can choose to stop taking part at any time without giving a reason, and your regular NHS medical care will not be affected in any way.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Germany

Common questions

What is an electrical cardioversion?

It is a short, routine hospital procedure where a carefully controlled electrical pulse is delivered to your chest while you are under a light anaesthetic, resetting your heart back into a normal rhythm.

What is a placebo and why is it used?

A placebo is a tablet that looks and tastes identical to the real medicine but contains no active ingredient. It helps researchers prove whether any improvements are truly caused by colchicine.

Will I know if I am getting colchicine or the placebo?

No. This is a 'double-blind' study, meaning neither you nor your doctors will know which tablet you are taking, ensuring the study results are completely fair and unbiased.

What happens if my irregular heart rhythm returns during the study?

Your study team will continue to care for you as normal. They may offer you standard treatments, which can include medication adjustments or another cardioversion procedure if needed.

Can I leave the study if I change my mind?

Yes. You are free to withdraw from the trial at any point. Your decision will not change your relationship with your healthcare team or affect the quality of your care.