The extent of improvement in left atrial (LA) function after radiofrequency catheter ablation (RFCA) in patients with paroxysmal atrial fibrillation (PxAF) and its association with heart failure with preserved ejection fraction (HFpEF) remain unclear. This study aims to explore whether there is a difference in the improvement of LA function after RFCA in patients with PxAF combined with HFpEF compared to those without HFpEF. Patients with PxAF receiving RFCA were enrolled. LA volume index (LAVI), LA emptying fraction (LAEF), and LA peak reservoir strain (LA RS) were assessed using echocardiography at baseline and three months after RFCA. Changes in these parameters were compared between patients with a high probability of HFpEF (hp-HFpEF) and those with a medium or low probability of HFpEF (lp-HFpEF), as determined by the H2FPEF score. A total of 147 patients (mean age 62.6 years
63.3% males) were recruited (hp-HFpEF = 30). Baseline LA function differed significantly between patients with hp-HFpEF and those with lp-HFpEF. Differences included LAVI, LAEF, and LA RS (all P <
0.01). The improvement in LA function 3 months after RFCA was significantly different between the two groups, even after adjusting for confounding factors. Specifically, patients with hp-HFpEF experienced greater reductions in LAVI, more improvement in LAEF, and greater improvement in LA RS compared to patients with lp-HFpEF. A high probability of HFpEF was correlated with greater improvement in LA function following RFCA in patients with PxAF. The clinical trial registration number: ClinicalTrials.gov NCT05266144.