Abstract
BACKGROUND: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Atrial remodeling often leads to impaired clinical outcomes after AF ablation. Understanding the factors influencing AF recurrence after ablation is crucial for improving patient prognosis. This study aimed to investigate the relationship between left atrial (LA) morphologic heterogeneity, quantified by fractal dimension (FD), and AF recurrence, as well as the impact on European Heart Rhythm Association (EHRA) symptom scores following ablation. METHODS: This study retrospectively collected the data of patients with AF who underwent their first radiofrequency ablation procedure at Lanzhou University Second Hospital between October 2019 and September 2022 and underwent cardiac computed tomography angiography (CTA) within 3 days before the procedure. Patients with less than 1 year of follow-up or those who did not meet the inclusion criteria were excluded from the analysis. On the cardiac CTA images, we calculated the FD of each patient's LA using fractal analysis. Cox proportional risk models were used to calculate the risk ratios for predictors of AF recurrence and for predictors of EHRA symptom score non-improvement. RESULTS: A total of 512 patients with AF were included with a median follow-up of 29 (range, 18-37) months, of which 349 had paroxysmal AF and 163 had persistent AF, 341 were male and 171 were female, 146 had recurrence of AF and 366 did not have recurrence, and 48 had improvement of EHRA symptoms and 98 did not have improvement. Cox regression analysis showed that LA-FD was an independent predictor of recurrence [hazard ratio (HR) =16.056, 95% confidence interval (CI): 7.493-34.406, P<0.001] and non-improvement in EHRA symptom score (HR =10.500, 95% CI: 3.086-35.728, P<0.001) after AF ablation. In patients with paroxysmal and persistent AF, LA-FD (HR =21.750, 95% CI: 8.533-55.444, P<0.001; HR =7.291, 95% CI: 1.977-26.896, P<0.05) is also an independent predictor of recurrence after AF ablation. Furthermore, patients with a larger LA-FD (>1.208) had a higher incidence of AF recurrence and EHRA symptom score non-improvement than those with a smaller LA-FD (<1.208, P<0.05). CONCLUSIONS: A larger LA-FD (>1.208) on cardiac CTA could be a predictor for adverse LA remodeling and was independently associated with recurrence and non-improvement of the EHRA symptom score after AF ablation.