Atrial fibrillation (AF) is the most common arrhythmia in humans, affecting more than 40 million people worldwide. Radiofrequency catheter ablation (RFCA) was first introduced as a treatment for AF by Haïssaguerre M in the late 1990s. This procedure quickly became the treatment of choice, especially for symptomatic patients with AF refractory to medication. However, up to 45% of patients may experience AF recurrence within 12 months after RFCA. In this setting, AF recurrence is likely multifactorial, including atrial remodeling, local fibrosis or incomplete ablation due to failure in locating the trigger. Additionally, patients with obesity, sleep apnea, hypertension, or diabetes are at an increased risk of AF recurrence after RFCA. Inflammation is increasingly recognized as a potential key factor in AF recurrence and may arise both from the healing response of heart tissue post-ablation or from chronic low-grade inflammation, as observed in many risk factors. Here, we present an original study by Wang et al, which investigated the combination of the systemic immune-inflammation index-a marker developed to assess overall inflammatory status-and the APPLE score, designed to predict AF recurrence following RFCA. The study found that using both indicators together improved the accuracy of AF recurrence prediction. These findings underscore the significant role of inflammation in cardiovascular disease and demonstrated its impact on AF recurrence after RFCA. Further research is warranted to validate the combined use of these two scores in clinical settings for predicting AF recurrence following catheter ablation.

Atrial fibrillation (Afib) is a common arrhythmia with significant public health implications, affecting millions of individuals worldwide. Catheter ablation (CA) is an established treatment for drug-resistant Afib, yet recurrence remains a major concern, impacting quality of life in a significant portion of patients. Inflammation plays a critical role in the recurrence of Afib after ablation, with systemic inflammatory markers such as C-reactive protein being linked to higher recurrence rates. In this editorial, we discuss the study by Wang et al, published in the latest issue, which investigates the predictive role of the systemic immune inflammation index (SII) in Afib recurrence following radiofrequency CA. Elevated pre-ablation SII levels are identified as an independent predictor of recurrence, significantly enhancing the predictive power of the APPLE score. Integration of SII improved the APPLE score's predictive performance, as shown by enhanced area under the curve, net reclassification improvement, and integrated discrimination improvement. This combined model highlights the importance of both structural and inflammatory factors in Afib recurrence, offering a more personalized approach to patient management. Additionally, the affordability and accessibility of SII enhance its practicality in clinical workflows. The study by Wang et al underscores the potential of integrating SII with existing scoring systems to refine risk stratification and optimize treatment strategies. Future research should validate these findings across diverse populations, explore limitations such as the potential influence of comorbidities on SII reliability, and investigate additional biomarkers to enhance predictive accuracy.

The recurrence of atrial fibrillation (AF) in patients after successful radiofrequency catheter ablation (RFCA) appears to be an unresolved clinical issue and needs to be clearly elucidated. There are many factors associated with AF recurrence, such as duration of AF, male sex, concomitant heart failure, hemodynamic parameters, chronic obstructive pulmonary disease, hypertension, obstructive sleep apnea, hyperthyroidism, smoking and obesity. However, the inflammatory changes are strongly associated with electrical and structural cardiac remodeling, cardiac damage, myocardial fibrotic changes, microvascular dysfunction and altered reparative response. In this context, biomarkers reflecting the different stages of AF pathogenesis deserve thorough investigation. The authors of the retrospective study revealed that one-year recurrence rate of non-valvular AF in the high systemic immune inflammation (SII) index group was significantly increased compared to that of the low SII index group and provided additional predictive value to the APPLE. Furthermore, the authors suggest that this biomarker may help physicians to optimize the selection of AF patients and to develop a personalized treatment approach. In conclusion, the SII index may serve as a valuable indicator of recurrent AF in patients after RFCA and may be a biomarker with plausible predictive value for poor clinical outcomes.