Clinical Research Directory

Inclusion Criteria: * Participants who have voluntarily provided written informed consent to participate. * Adults aged 19 years or older. * Life expectancy of at least 1 year. * Diagnosis of atrial fibrillation within the past 1 year. * Participants with an indication for antiarrhythmic drug therapy (Dronedarone or Class Ic agents). Exclusion Criteria: * History of failure with prior antiarrhythmic drug therapy. * Confirmed severe structural heart disease (e.g., heart failure with reduced ejection fraction \[LVEF \<= 40%\], moderate or severe mitral stenosis, mechanical heart valve replacement, or dilated cardiomyopathy). * Diagnosis of permanent atrial fibrillation. * Severe renal impairment (eGFR \< 30 mL/min/1.73m\^2 or on dialysis) or severe hepatic impairment (Child-Pugh class B or higher) that restricts the use of antiarrhythmic drugs. * Known contraindications to dronedarone or Class Ic antiarrhythmic drugs. * Participation in another clinical trial within 3 months prior to randomization. * Participants who do not agree to refrain from participating in another clinical trial within 14 days after their participation in this study ends. * Pregnant or breastfeeding women, or women of childbearing potential who do not agree to use effective contraception during the study. * Any other condition that, in the opinion of the investigator, makes the participant unsuitable for study participation.