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Colchicine after Electrocardioversion to Prevent Recurrence of Atrial Fibrillation in Adult Patients

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What is this trial about?

A plain-language summary of the goals, design and what participants do

The trial focuses on Atrial Fibrillation, a condition where the heart beats irregularly and can cause dizziness, shortness of breath, or fatigue. Participants will receive either colchicine, a medicine that helps lower inflammation, or a placebo tablet that looks the same but contains no active drug. All participants will have undergone electrocardioversion, a short electric shock used to restore a normal heart rhythm, before starting the study. The purpose of the study is to determine how often the irregular heartbeat returns within six months after the procedure.

After the initial shock treatment, participants will take the assigned tablet daily for a period of several weeks, with follow‑up visits scheduled to check heart rhythm and record any repeat procedures or additional medications. Researchers will monitor for any return of the irregular heartbeat at one month, three months, and six months, and will also note any hospital visits that were not planned. The overall study period lasts up to six months for each participant.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Enrollment and randomization

    After signing informed consent, you are assigned to either the colchicine group or the placebo group.

    Assignment is performed by the study team using a random process.

  2. Step 2

    Baseline assessment

    A set of baseline measurements is taken, including medical history, current medications, and basic tests.

    The information is recorded before the electrocardioversion procedure.

  3. Step 3

    Electrocardioversion (ecv)

    You undergo electrocardioversion, a procedure that uses a controlled electric shock to restore normal heart rhythm.

    The procedure is performed in a clinical setting under medical supervision.

  4. Step 4

    Start study medication

    Immediately after the electrocardioversion, you begin taking the study medication.

    If assigned to the colchicine group, you take colchicine tablets; if assigned to the placebo group, you take identical placebo tablets.

    Each tablet contains 0.5 mg of the active substance (colchicine) or none for the placebo.

  5. Step 5

    Medication dosing

    The prescribed dose is a total of 3 mg per day, taken orally.

    This corresponds to six 0.5 mg tablets each day, divided into equal doses (for example, three tablets in the morning and three tablets in the evening).

    The medication is taken for the entire 6‑month observation period after the electrocardioversion.

  6. Step 6

    Follow‑up visits

    You attend scheduled visits at approximately 1 month, 3 months, and 6 months after the electrocardioversion.

    At each visit, your heart rhythm is checked, and any recurrence of atrial fibrillation is recorded.

    You are also asked about use of other anti‑arrhythmic drugs, hospitalizations, and any side effects.

  7. Step 7

    Final assessment

    At the 6‑month visit, a final evaluation is performed to document any atrial fibrillation recurrences and other outcomes.

    The data are collected for the trial’s primary and secondary endpoints.

Who can join the trial?

5 criteria

  • You must be older than 18 years (an adult).
  • You need to be scheduled for electrical cardioversion (ECV) – a short, controlled electric shock used to try to reset the heart’s rhythm.
  • You must have atrial fibrillation confirmed by an ECG (a simple test that records the heart’s electrical activity) before the ECV.
  • The ECV must successfully change the heart rhythm from atrial fibrillation to a normal rhythm called sinus rhythm, and this normal rhythm must stay steady for at least one hour after the procedure.
  • You must be able to understand the study and sign a written informed consent form, showing that you agree to take part.

Who cannot join the trial?

17 criteria

  • If your atrial fibrillation continues or comes back within one hour after the procedure that tries to restore a normal heartbeat (cardioversion or ECV), you cannot join the study.
  • If your doctor says you must take Colchicine for another medical reason, you are not eligible.
  • If you are taking medicines that strongly block the liver enzyme CYP3A4 or the transport protein P‑glycoprotein, you cannot participate.
  • If you have a serious stomach or intestinal illness (gastrointestinal disease), you are excluded.
  • If you have obvious liver problems (hepatic disease), you cannot join.
  • If you have serious kidney problems (renal disease), you are not eligible.
  • If you are a man who is actively trying to father a child, you cannot take part.
  • If there is any other reason your doctor says Colchicine is unsafe for you, you are excluded.
  • If you cannot digest certain sugars because of galactose intolerance, total lactase deficiency, or glucose‑galactose malabsorption, you cannot participate.
  • If you have a significant blood disorder (blood dyscrasia), you are not eligible.
  • If you have a weakened immune system (immunosuppression), you cannot join.
  • If you are pregnant, breastfeeding, or could become pregnant and are not using a highly reliable form of birth control during the study and for three months after, you are excluded.
  • If your doctor expects you to live less than one year (life expectancy < 1 year), you cannot participate.
  • If you have already taken part in the COLECTRO‑AF trial before, you are not eligible.
  • If your heart rhythm was anything other than atrial fibrillation before the cardioversion, you cannot join.
  • If you had a pulmonary vein isolation procedure within the past three months or plan to have one in the next three months, you are excluded.
  • If you are known to be allergic or overly sensitive (hypersensitivity) to Colchicine, you cannot participate.
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Investigated drugs

Colchicine is a medication that reduces inflammation in the body. In this trial, participants take colchicine after they have an electrical shock (electrocardioversion) to restore a normal heart rhythm. The researchers want to see if colchicine can help keep the heart rhythm steady and prevent the irregular heartbeat (atrial fibrillation) from coming back within the next six months. The drug is taken by mouth as a tablet.

What is already known about the treatment

  • Placebo

    The placebo is taken as an oral tablet that looks identical to the active drug, with a cream‑white color and a 0.5 mg imprint. It contains no active ingredient and is used only to compare the effects of the real medication. In clinical studies it helps researchers see whether any changes are due to the drug or other factors. The tablet is safe and has no therapeutic effect.

  • Colchicine

    Colchicine is taken as an oral tablet, each containing 0.5 mg of the drug. It is an established medication used mainly for gout and to reduce inflammation after heart procedures, and it is well described in medical literature. In this trial it is tested to see if it can lower the chance of atrial fibrillation coming back after electrical cardioversion. The drug works by stopping certain cells from moving and releasing chemicals that cause inflammation, which helps calm the heart rhythm.

Investigated diseases

Atrial Fibrillation - Atrial fibrillation is an irregular and often rapid heart rhythm that originates in the upper chambers of the heart. The electrical signals become chaotic, causing the atria to quiver instead of contracting normally. This leads to an uneven heartbeat that can change in speed and pattern over time. Episodes may start suddenly and last from minutes to days, and they can recur frequently. As the condition continues, the irregular rhythm can become more persistent, affecting the overall rhythm of the heart.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-516033-12-00Protocol codeCOLECTRO-AFEstimated enrolment127 patientsSponsorUniversitaetsspital Basel

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