The COLchicine and Atrial FIBrillation Trial

Inclusion criteria

• Living address in the Capital Region of Denmark
• Age \> 18
• Diagnosed with paroxysmic/persistent AF.
• Planned or acute admission for cardioversion of AF with successful outcome.
• Female participants should either not be of childbearing potential, defined as postmenopausal for at least 1 year or surgically sterile, or is of childbearing potential and practicing one of the following methods of contraception throughout the study and for 30 days after study completion: Hormonal contraception (oral contraceptives, contraceptive implant, injectable birth control, contraceptive patch, or vaginal ring) or intrauterine device
• Participants will have given written, informed consent and are able and willing to comply with the requirements of the study protocol.
• Optimal background therapy (in relation to comorbidities and development of heart failure / thromboembolic event) for AF as judged by the investigator.

Exclusion criteria

• Colchicine treatment for another cause, e.g. gout
• Allergy/hypersensitivity to colchicine
• Uncontrolled hypertension (systolic BP \>180 mmHg or diastolic BP \>110 mmHg)
• History of malignancy of any organ system excluding a successfully treated non-metastatic cutaneous squamous cell or basal cell carcinoma, localized prostate cancer and/or localized carcinoma in situ of the cervix
• Cirrhosis, chronic active hepatitis or other severe hepatic disease
• Hemodialysis
• Estimated glomerular filtration rate (eGFR) \< 60 mL/min/1.73 m2
• Systemic treatment with moderate or strong cytochrome P450 3A4 (CYP3A4) inhibitors or P-glycoprotein inhibitors (list in Appendix 1)
• Permanent AF
• Female participants who are pregnant, lactating, or considering becoming pregnant during the study or for 6 months after study completion
• Significant drug or alcohol abuse during the last year
• Current use of or plans to initiate chronic systemic steroid therapy during the study (topical or inhaled steroids are allowed)
• Planned ablation procedure as treatment for AF
• If cardiovascular surgery or ablation has been done the past three months prior to inclusion.
• Chronic inflammatory bowel disease (Crohn's disease or ulcerative colitis) or chronic diarrhea
• Use of other investigational drugs within 30 days of the time of enrollment
• Any surgical or medical condition, which in the opinion of the investigator, may place the patient at higher risk from his/her participation in the study, or is likely to prevent the patient from complying with the requirements of the study or completing the study.
• Suspected AF, confirmed with ECG, at time of inclusion and randomization