NCT05844501 · Indiana University
Ondansetron for the Management of Atrial Fibrillation
What this study is about
"Afib" is a common irregular heartbeat. Afib can cause stroke, blood clots, dementia and death. Medicines used to treat Afib often do not work well and can cause serious side effects. Clinicians need medicines that work better for Afib. Medicines for Afib work by blocking a current in the heart called a potassium current. There is a newer potassium current called IKas that can contribute to Afib.
View original scientific description
"Afib" is a common irregular heartbeat. Afib can cause stroke, blood clots, dementia and death. Medicines used to treat Afib often do not work well and can cause serious side effects. Clinicians need medicines that work better for Afib. Medicines for Afib work by blocking a current in the heart called a potassium current. There is a newer potassium current called IKas that can contribute to Afib.
Interventions
DRUG
Ondansetron 8mg
Ondansetron 8 mg orally twice daily for 28 days
DRUG
Placebo
Matched placebo orally twice daily for 28 days
Primary outcome measures
Atrial fibrillation burden
Time frame: Total duration of study (28 days)
Burden of atrial fibrillation, defined as overall percentage of time in atrial fibrillation.
Ventricular rate control
Time frame: 7 days after initiation of ondansetron/placebo
Maximum heart rate while in atrial fibrillation
Ventricular rate control
Time frame: 14 days after initiation of ondansetron/placebo
Maximum heart rate while in atrial fibrillation
Ventricular rate control
Time frame: 21 days after initiation of ondansetron/placebo
Maximum heart rate while in atrial fibrillation
Ventricular rate control
Time frame: 28 days after initiation of ondansetron/placebo
Maximum heart rate while in atrial fibrillation
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Men and women 18-100 years of age
- ECG-verified AF and/or atrial flutter requiring elective catheter ablation
- Receiving guideline-recommended anticoagulation (if CHA2DS2-VASc score is 0 (men) or 1 (women), anticoagulation can be omitted)
Exclusion criteria
- Women of childbearing potential
- Subject reported syncope of unknown origin within the previous 6 months
- Diagnosis of active thyrotoxicosis
- Diagnosis AF from reversible noncardiac causes
- Diagnosis of acutely decompensated heart failure
- Left ventricular ejection fraction less than or equal to 20%
- New York Heart Association class IV heart failure
- Diagnosis of severe liver disease (Child-Pugh score greater than or equal to 10)
- Cardiac surgery (preceding 2 months)
- Not receiving anticoagulation due to contraindications (as determined by treating physician and recorded in the medical record)
- Pretreatment QRS \> 180 ms, QTc \> 450 ms within two weeks of screening visit
- Heart rate \< 5
Where
- Indianapolis, Indiana
Collaborators
American Heart Association, Purdue University
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Feb 4, 2026 · Source of record for eligibility and locations