A retrospective analysis of 276 patients with AF who underwent single-operator RCA at the General Hospital of Northern Theater Command between January and December 2023 was conducted. The study population consisted of consecutive patients treated by the same operator in 2023. The inclusion criteria were as follows: (1) RCA was performed by a single operator, Ming Liang; (2) AF was confirmed by electrocardiogram (ECG) or Holter monitoring; and (3) patients met the indications for RCA and successfully underwent the procedure. Twenty-six patients were excluded for the following reasons: incomplete postoperative ECG or Holter monitoring (n = 0), missing baseline data (n = 20), missing 18 months postoperative BMI or recurrence data (n = 4), and severe valvular heart disease (n = 2). Paroxysmal atrial fibrillation (PAF) was defined as AF episodes lasting < 7 days with spontaneous conversion to sinus rhythm; persistent atrial fibrillation (SAF) was defined as episodes lasting ≥ 7 days or requiring medical intervention for conversion^[11]. Patients were categorized by AF type into the SAF group (n = 140) and the PAF group (n = 110). The duration of persistent AF was assessed using ECG or 24 h Holter monitoring records. Pulmonary vein isolation was performed by a single operator in all patients. Clinical data were extracted from the hospital’s electronic medical record system.

This study was conducted in accordance with the principles of the Declaration of Helsinki. The study protocol was reviewed and approved by the Ethics Committee of the General Hospital of Northern Theater Command [Approval No. Y (2025) 529]. The requirement for informed consent was waived by the institutional review board given the retrospective design and complete anonymization of all patient data.

Preoperative transesophageal echocardiography was routinely performed to assess for thrombus. Antiarrhythmic medications were discontinued for at least five half-lives before the procedure. Electrophysiological studies and ablation procedures were performed under fentanyl-assisted conscious sedation. In brief, two right femoral venous accesses with 8.5-F sheaths were used for transseptal puncture. After transseptal puncture, intraoperative heparinization was used to maintain an activated clotting time of 300-350 s. A 10-pole catheter was inserted into the coronary sinus via the left femoral or right jugular venous access. The left atrium was mapped using a 20 mm 10-pole circular or adjustable curved mapping catheter to establish a three-dimensional model of the left atrium. A 3.5 mm open-tip irrigated ablation catheter was used to ablate the right pulmonary vein antrum first, followed by the left pulmonary vein antrum. Radiofrequency energy was delivered in a wide-area circular pattern within 0.5-1.5 cm of the corresponding pulmonary vein ostium. Ablation parameters included radiofrequency energy of 35-40 W, contact force of 5-15 g, and impedance of 120-140 ohms. The target ablation index was 360-380 for the posterior wall and 400-420 for the anterior wall. A circular or PentaRay catheter was then placed in each of the four pulmonary veins to confirm isolation. If isolation was incomplete, additional ablation was performed as needed. Intravenous isoproterenol was administered to induce non-pulmonary vein triggers. The durability of pulmonary vein isolation was confirmed 30 min after initial documentation of isolation. If AF persisted after circumferential pulmonary vein ablation, direct current cardioversion was performed to restore sinus rhythm.

All patients were followed at 3, 6, 9, 12, and 18 months after the procedure by telephone or outpatient visits. An ECG was recorded at each follow-up visit, and 24 h Holter monitoring was performed at the 3 and 18 months visits. If symptoms suggested a possible arrhythmia recurrence, additional ECG or 24 h Holter monitoring was performed. All patients received antiarrhythmic and anticoagulant therapy for at least three months to prevent early recurrence and reduce thromboembolic risk. Proton pump inhibitors were administered for at least six weeks. The primary outcome was freedom from clinical AF recurrence at 18 months after the procedure. AF recurrence was defined as any documented episode of AF lasting at least 30 s. AF episodes occurring during the initial 3 months blanking period after the procedure were classified as early recurrence. Only recurrences after the blanking period were classified as clinical recurrence. After the blanking period, antiarrhythmic therapy was prescribed if ECG or 24 h Holter monitoring showed recurrent AF/atrial tachycardia or frequent atrial premature beats. Additional outcomes included procedure-related complications, such as groin hematoma and left atrial appendage electrical isolation, as well as other safety endpoints.

The initial dataset included demographic and clinical characteristics, including age, sex, preoperative BMI, left atrial diameter, serum creatinine, N-terminal pro-B-type natriuretic peptide (NT-proBNP), AF duration, left ventricular ejection fraction, hypertension, diabetes, heart failure, obstructive sleep apnea, coronary artery disease, and history of stroke. Postoperative BMI was assessed only at the 18 months follow-up (a single time point); only 18 months BMI data were complete, and interim BMI data were not analyzed because of partial missingness. Postoperative BMI was categorized using predefined cutoffs as follows: normal weight, < 24 kg/m²; overweight, 24 ≤ BMI < 28 kg/m²; and obesity, ≥ 28 kg/m². BMI was measured in the morning after an overnight fast.

Before formal analysis, data accuracy and outliers were verified through double-entry cross-checking and review of the original medical records to ensure data integrity. The normality of continuous variables was assessed using the Shapiro-Wilk test and Q-Q plots.

Data analysis was performed using SPSS version 29.0. Continuous variables are expressed as the mean ± standard deviation or median (interquartile range). Normally distributed variables were compared using Student’s t-test, and non-normally distributed variables were compared using the Mann-Whitney U test. Categorical variables are presented as frequencies (n) and percentages (%) and were analyzed using the chi-squared test or Fisher’s exact test, as appropriate. The Kaplan-Meier method was used to estimate recurrence-free survival during follow-up, and survival distributions were compared using the log-rank test. Multivariate Cox regression was performed to examine the association between postoperative BMI category and recurrence, with adjustment for potential confounders including age, sex, left atrial diameter, left ventricular ejection fraction (LVEF), AF duration > 12 months, and comorbidities (hypertension, diabetes, heart failure, obstructive sleep apnea, coronary artery disease, and stroke). Variables were selected for the multivariate model based on univariate analysis (P < 0.10) and clinical relevance. A two-sided P < 0.05 was considered statistically significant.

The main strengths of this study are as follows. First, all procedures were performed by the same experienced operator, minimizing the potential impact of procedural variability and enhancing the reliability of the findings. Second, strict exclusion criteria, such as patients with missing baseline data, incomplete postoperative follow-up data, or severe valvular heart disease, improved the homogeneity of the study cohort.

This study has several limitations. First, because this was a single-center retrospective study with a relatively limited sample size (n = 250), selection bias may have been introduced, and generalizability may be limited. No a priori sample size calculation was performed, which may have affected the statistical power of subgroup analyses. The retrospective design also precludes causal inference. Second, postoperative BMI was assessed only at the 18 months follow-up; repeated BMI measurements during follow-up were not available. Therefore, potential weight fluctuations or trajectories could not be captured. Third, the limited sample size may have reduced the statistical power of subgroup analyses; for example, it was not possible to further analyze the association between postoperative BMI and AF recurrence in subgroups defined by AF duration, age, or comorbidities. Fourth, this study relied mainly on BMI to assess postoperative obesity. BMI reflects the ratio of weight to height but does not distinguish body fat distribution, whereas measures of abdominal obesity may better reflect visceral adiposity. Finally, although the multivariate Cox model adjusted for several clinically relevant confounders, residual confounding from unmeasured factors may remain, including changes in antihypertensive or antidiabetic medications after the blanking period and adherence to weight management.

Future studies should address these limitations by conducting multicenter prospective cohort studies with larger sample sizes and patients from different regions and hospitals to further evaluate the generalizability of these findings. Randomized controlled trials are also needed to compare conventional management plus intensive weight intervention with conventional management alone for reducing recurrence after AF RCA, with dynamic recording of weight changes to directly assess the clinical efficacy of weight intervention. Future studies should also incorporate more refined measures of obesity, such as waist circumference and body fat percentage, together with inflammatory and metabolic biomarkers, to establish multidimensional recurrence prediction models that integrate clinical and biomarker data. Finally, follow-up should be extended to 3-5 years to dynamically assess postoperative BMI and evaluate the impact of postoperative BMI changes on long-term recurrence and adverse cardiovascular events, thereby providing more comprehensive evidence for long-term management strategies.

In this retrospective analysis, postoperative obesity assessed at a single time point (18 months) was associated with a higher risk of recurrence after RCA for AF. Specifically, among patients with PAF, a BMI ≥ 28 kg/m² at 18 months was associated with an increased recurrence risk. Among patients with SAF, higher postoperative BMI grades at 18 months and AF duration exceeding 12 months were also associated with recurrence.