Background: Inflammation plays an important role in the initiation of atrial fibrillation (AF) and the development of fibrosis following pulmonary vein isolation (PVI). We aimed to investigate whether early post-PVI levels of C-reactive protein (CRP), white blood cells, tumour necrosis factor alpha (TNF-α) and transforming growth factor beta 1 (TGF-ß1) are associated with long-term arrhythmia recurrence. Methods: This prospective observational study included 48 patients with paroxysmal AF undergoing PVI. Peripheral venous blood samples were collected on the day of hospitalisation (T0), immediately after the procedure (T1) and after 24 h (T2), seven days (T3) and one month (T4) following the procedure. Blood samples were obtained from the coronary sinus (CS) before and after PVI. CRP levels, leukocyte (LKc) and neutrophile (Neu) counts were determined. TGF-β1 and TNF-α were analysed using the enzyme-linked immunosorbent assay (ELISA). After discharge, follow-up visits were scheduled at seven days and one-, three-, six-, nine- and twelve-months post-ablation, with 24 h Holter monitoring at each visit. Results: Patients were allocated into a recurrent and a non-recurrent group. Baseline characteristics did not differ between the groups, except for the duration of AF, which was found to be a significant arrhythmia recurrence predictor. Patients in the non-recurrent group had statistically significantly higher LKc at all time points, and Neu at T2 and T3. CRP and TGF-β1 concentrations were significantly higher in the non-recurrent group, while TNF-α concentration was significantly higher in the recurrent group at the T2 time point. Significantly higher concentrations of CS TNF-α at T1 and TGF-β1 at T0 and T1 were documented in the non-recurrent group. Conclusions: The study shows that an enhanced inflammatory response early after PVI, characterised by increased CRP, WBC and TGF-β1 levels, may play a protective role against late arrhythmia recurrence.

Background and Objectives: Conduction disorders (CDs) and permanent pacemaker implantation (PPI) remain among the most common complications after transcatheter aortic valve implantation (TAVI). Given their potential impact on long-term outcomes, improved preprocedural identification of patients at high risk for new-onset CDs is increasingly important. We investigated whether selected preprocedural inflammatory and fibrotic biomarkers, along with echocardiographic indices of regional myocardial remodeling, were associated with new-onset CDs after TAVI. Materials and Methods: This single-center prospective observational study included 112 patients with severe aortic stenosis undergoing TAVI. Peripheral blood samples were obtained within 24 h before TAVI for measurement of inflammatory and fibrotic biomarkers, including interleukin-6 (IL-6), C-reactive protein (CRP), CRP-to-albumin ratio (CAR), procalcitonin, ferritin, lactate dehydrogenase, and transforming growth factor-β1. The primary outcome was the occurrence of new-onset CDs during the index hospitalization or within three months after TAVI. Results: New-onset CDs occurred in 58 patients (51.8%). IL-6 showed the strongest association with the outcome in univariable analysis (OR per 1-SD increase, 9.55; 95% CI 3.00–30.40; p < 0.001), remained associated after adjustment for selected clinical and procedural predictors in exploratory models (adjusted OR 10.70; 95% CI 2.43–47.07; p = 0.002), and demonstrated the highest, although moderate, discriminatory performance among the evaluated biomarkers (AUC 0.730; 95% CI 0.637–0.823). CRP and CAR were higher in patients with CDs and were significant in univariable analysis, but showed weaker and less consistent adjusted associations. Among echocardiographic markers, AB strain ratio ≥ 2 was the most consistent imaging correlate in exploratory biomarker–echocardiographic models. Conclusions: Elevated preprocedural IL-6 was the biomarker most consistently associated with new-onset CDs after TAVI. These findings suggest that higher preprocedural IL-6 levels may reflect patient-specific susceptibility to new-onset CDs after TAVI and could have potential value as an adjunctive biomarker, alongside echocardiographic assessment, for preprocedural risk evaluation, with further validation required in larger prospective studies.