Safety of flecainide acetate compared with amiodarone hydrochloride and sotalol in patients with atrial fibrillation and stable coronary artery disease

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What is this study about?

The study involves people who have both coronary artery disease and atrial fibrillation. Coronary artery disease is a condition where the arteries that bring blood to the heart become narrowed or blocked, and atrial fibrillation is an irregular heartbeat that can cause symptoms such as palpitations, fatigue, or shortness of breath. Participants will be randomly assigned to receive either the test medication flecainide or one of two standard treatments, amiodarone or sotalol, all taken by mouth.

The purpose of the study is to compare the safety of flecainide with that of the standard anti‑arrhythmic drugs in this patient group. After a short screening period, participants will start taking the assigned medication and will have regular clinic visits for check‑ups over a minimum of one year. During the study, doctors will record any serious problems such as death, need to stop the medication because of side effects, or unexpected hospital stays for heart failure or heart attacks.

Safety will be evaluated using several heart‑related measurements. The study will look at the QTc interval, a number on an electrocardiogram (ECG) that shows how long the heart’s electrical system takes to recharge, and the QRS duration, which reflects how quickly the heart’s electrical signal spreads. Heart‑pumping ability will be checked with the left ventricular ejection fraction, and a blood test called NT-proBNP will be used to see if the heart is under stress. Major adverse cardiovascular events, often abbreviated as MACE, such as heart‑related death, non‑fatal heart attacks, or strokes, will also be tracked.

1 enrollment and consent

after you agree to participate, you will sign a consent form that explains the study and your rights.

2 baseline assessment

you will undergo a series of initial examinations that include a physical check, blood tests, an electrocardiogram (ecg) and an ultrasound of the heart (echocardiogram).

questionnaires about your quality of life and heart‑related symptoms will be completed at this visit.

3 randomization to treatment group

based on a computer‑generated list, you will be assigned to one of two groups.

if you are placed in the flecainide group, you will receive a prolonged‑release capsule containing 300 mg of flecainide acetate taken by mouth once daily.

if you are placed in the standard‑of‑care group, you will receive either amiodarone tablets (600 mg total per day) or sotalol tablets (320 mg total per day), also taken by mouth once daily.

4 start of medication

the assigned medication will be started immediately after randomization.

you will take the tablet or capsule each morning with water.

the medication will be continued for the entire study period, which is a minimum of twelve months.

5 regular follow‑up visits

you will return to the clinic for follow‑up visits at approximately 1 month, 3 months, 6 months, and 12 months after starting the medication, and then every six months thereafter until the study ends.

at each visit a clinician will check your heart rhythm with an ecg, repeat blood tests, review any side effects, and ask you to complete the same quality‑of‑life questionnaires used at baseline.

6 monitoring for safety events

throughout the study you must report any new symptoms, hospital admissions, or medication side effects to the study team as soon as possible.

serious events such as death, discontinuation of the study drug because of an adverse reaction, or unplanned hospitalisation for heart failure or a heart attack are recorded as part of the primary safety outcome.

7 final assessment and study completion

after at least one year of treatment, a final visit will be performed.

the final visit includes a complete physical examination, repeat ecg, echocardiogram, blood tests, and the same set of questionnaires completed at the start of the study.

after this visit the study medication will be stopped and you will be advised on any further care needed.

Who Can Join the Study?

Voluntary written consent: You must sign a written agreement to join the study, and you do it willingly.
Age requirement: You must be at least 18 years old when you sign the consent form.
Irregular heartbeat condition: You must have non‑permanent atrial fibrillation (a common type of irregular heartbeat) or ectopic atrial tachycardia (a fast heartbeat that starts outside the normal pacemaker), and you must be planning to treat it by trying to keep a normal rhythm. This must have been recorded by any test in the year before you sign.
Stable coronary artery disease (narrowing of the heart’s blood vessels that is not causing chest pain or lack of blood flow). This can be shown by any one of the following:
- You have had a prior percutaneous coronary intervention (a small tube placed to open a blocked artery).
- You have had a prior heart attack that was treated with surgery or a bypass operation more than 3 months ago.
- An invasive coronary angiography (a special X‑ray of the heart’s arteries) shows at least a 50 % narrowing in a major heart artery.
- A coronary CT scan (a detailed 3‑D picture of the heart’s arteries) shows a CAD‑RADS stage of 3 or higher, and you have no signs of reduced blood flow on exercise testing, myocardial perfusion imaging (MIBI), stress cardiac MRI, or fractional flow reserve measurements.
Heart pumping ability: Your left ventricular ejection fraction (a measure of how well the main pumping chamber of the heart works) must be 45 % or higher on any heart imaging test.

Who Cannot Join the Study?

Having a heart‑pumping ability measured as LVEF (left ventricular ejection fraction) less than 45%.
Having serious chronic kidney disease, shown by an eGFR (estimated glomerular filtration rate) below 40 mL/min.
Being expected to live less than one year.
Having severe heart failure, described as NYHA class III or IV (significant shortness of breath and limited activity).
Being pregnant, breastfeeding, planning to become pregnant, or possibly becoming pregnant without using a reliable birth‑control method.
Being unable to give written consent because of memory problems, mental illness, or other conditions that prevent understanding the study.
Already taking part in another trial that uses an experimental drug or device.
Currently taking the medicine amiodarone (a drug used to control heart rhythm).
Having a past reaction or intolerance to flecainide or to both sotalol and amiodarone.
Having unstable chest pain (unstable angina) or reduced blood flow to the heart that appears during stress tests.
Having a baseline QRS duration of 120 ms or longer on an ECG, unless a working pacemaker is already implanted.
Having a known inherited heart‑rhythm disorder (a channelopathy) such as Brugada syndrome or long QT syndrome.
Having a baseline corrected QT interval (Fridericia formula) of 500 ms or more, which indicates a prolonged heart‑electrical recovery time.
Having an advanced AV block (second‑ or third‑degree), a problem with the heart’s electrical signal passing from the atria to the ventricles.
Having sick sinus syndrome or a slow heart rate (sinus bradycardia) below 50 beats per minute.
Having clinically important low potassium (hypokalemia) or low magnesium (hypomagnesemia) that has not been corrected before starting the study drug.
Having thyroid problems that would prevent the use of amiodarone as standard care.
Being allergic to the study drug or any of its inactive ingredients.
Having a medical reason not to use AV‑slowing medicines such as beta‑blockers, diltiazem, or verapamil.
Having atrial fibrillation caused by a reversible condition (for example, an infection or thyroid issue).
Having an active blood clot inside the heart (intracardiac thrombus).
Having had a heart attack (acute coronary syndrome) within the three months before signing the consent.
Having had heart surgery, including coronary artery bypass, within the three months before signing the consent or having such surgery planned soon.
Having moderate or severe congenital heart disease according to current guidelines.
Having hypertrophic cardiomyopathy where the heart wall is thicker than 1.5 cm (abnormally thick heart muscle).

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Katholieke Universiteit te Leuven	Leuven	Belgium

Other Sites

Site Name	City	Country
Az St-Jan Brugge-Oostende A.V.	Brugge	Belgium
Jan Yperman Ziekenhuis	Ieper	Belgium
Ziekenhuis Oost Limburg	Genk	Belgium
Algemeen Ziekenhuis Delta	Roeselare	Belgium
Az Maria Middelares Gent	Gent	Belgium
AZ Turnhout	Turnhout	Belgium
Algemeen Ziekenhuis Groeninge	Kortrijk	Belgium
Vitaz	Sint-Niklaas	Belgium
AZ Rivierenland	Rumst	Belgium
AZ St.-Elisabeth Herentals VZW	Herentals	Belgium
Azorg	Aalst	Belgium
Uzekdhrlvv Od Arzqfvv	Edegem	Belgium
Iodwby	Bonheiden	Belgium

Trial status

Country	Status	Recruitment Start
Belgium	Not yet recruiting	01.07.2026

Trial locations

Investigated drugs:

Amiodarone is a medication that helps control irregular heartbeats. In this study it is used as a standard treatment to compare against the new drug being tested. It works by slowing down the electrical signals in the heart, which can help keep the rhythm steady for people with atrial fibrillation and coronary artery disease.

Flecainide is the drug being tested in the trial. It is also used to keep the heart’s rhythm regular, but it belongs to a different class of medicines than the standard treatments. The study is checking whether flecainide is safe and works as well as the usual medicines for patients with atrial fibrillation and stable coronary artery disease.

Sotalol is another medication commonly used to treat irregular heart rhythms. In this trial it serves as another standard‑of‑care comparison. Like amiodarone, sotalol helps control the heart’s electrical activity, and the researchers are using it to see how the new drug’s safety measures up against existing options.

Investigated diseases:

Coronary artery disease – A condition where the blood vessels that feed the heart become narrowed by the buildup of fatty deposits. Over time the narrowing can restrict the amount of blood reaching the heart muscle. This may cause episodes of chest discomfort, especially during physical activity. As the blockage grows, the heart may receive less oxygen, leading to a gradual increase in symptoms. The disease often develops slowly and can become more noticeable as the arteries continue to narrow.
Atrial fibrillation – An irregular heart rhythm in which the upper chambers of the heart beat rapidly and out of sync with the lower chambers. The disorder can begin with occasional brief episodes and may progress to more frequent or continuous episodes. It often causes a fluttering sensation in the chest, shortness of breath, or tiredness. The irregular beats can make the heart work less efficiently, and the pattern may become more persistent over time.

Trial ID:

2025-525121-13-00

Protocol code:

S69367

NCT ID:

NCT07405671

Trial Phase:

Therapeutic confirmatory (Phase III)

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Safety of flecainide acetate compared with amiodarone hydrochloride and sotalol in patients with atrial fibrillation and stable coronary artery disease

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?