Atrial fibrillation is frequently accompanied by tricuspid regurgitation and may contribute to right atrial and tricuspid annular remodeling, leading to progression of tricuspid regurgitation and adverse clinical outcomes. However, whether early rhythm control improves prognosis in patients with atrial fibrillation and tricuspid regurgitation remains unclear. This study will compare early rhythm control with usual care in these patients, using a composite outcome of cardiac death, heart failure admission, stroke, and tricuspid valve surgery.

Atrial fibrillation and tricuspid regurgitation frequently coexist in clinical practice. Atrial fibrillation may promote right atrial enlargement and tricuspid annular dilatation, which can aggravate functional tricuspid regurgitation over time. Conversely, significant tricuspid regurgitation may further increase right-sided volume overload, worsen atrial remodeling, and contribute to the persistence or progression of atrial fibrillation. This bidirectional relationship may lead to heart failure, thromboembolic events, and an increased need for tricuspid valve intervention.

Although early rhythm control has been shown to improve cardiovascular outcomes in selected patients with atrial fibrillation, its clinical benefit in patients with concomitant tricuspid regurgitation has not been well established. In particular, it remains uncertain whether maintaining sinus rhythm at an early stage can slow the progression of right-sided cardiac remodeling, reduce heart failure events, and improve long-term prognosis in this population.

This study is designed to evaluate the prognostic impact of early rhythm control compared with usual care in patients with atrial fibrillation and tricuspid regurgitation. The primary endpoint will be a composite of cardiac death, heart failure admission, stroke, and tricuspid valve surgery. By comparing these clinically meaningful outcomes between the two treatment strategies, this study aims to clarify whether early rhythm control should be considered as an active therapeutic approach in patients with atrial fibrillation complicated by tricuspid regurgitation.

The study will use retrospectively collected data from patients diagnosed with atrial fibrillation and tricuspid regurgitation between January 1, 2013 and December 31, 2023. Clinical outcomes will be assessed during this observation period.

Inclusion Criteria:

• Patients with concomitant atrial fibrillation and tricuspid regurgitation.

Exclusion Criteria:

• Patients with a history of valvular surgery
• Patients with congenital heart disease
• Patients with primary pulmonary hypertension
• Patients with CIED implantation prior to the diagnosis of tricuspid regurgitation
• Patients diagnosed with TR only after the initiation of rhythm control therapy for AF

The investigator emulated a sequential target trial comparing early rhythm control with usual care among patients with atrial fibrillation and tricuspid regurgitation, using data from the Korean National Health Insurance Service (K-NHIS) claims database.

The K-NHIS database represents the entire population of Korea. The K-NHIS database covers the total population of Korea. The NHIS database includes information on all individuals in Korea, such as demographics, diagnosis codes based on the International Classification of Diseases, 10th Revision (ICD-10), procedures, prescriptions (coded by ATC codes), utilization of healthcare services, and mortality linked to national statistics. The investigator further linked these data with the National Health Screening Program, which provides biennial standardized health examination results, including laboratory measurements such as serum creatinine and hemoglobin, using anonymized individual identifiers.

Individual participant data will not be shared because this study uses de-identified claims data from the Korean National Health Insurance Service (K-NHIS) database. The investigators are not permitted to provide or redistribute participant-level data under K-NHIS data use policies and privacy regulations.