The role of systemic inflammatory indices in predicting atrial fibrillation and its complications: a narrative review

Atrial fibrillation (AF) is associated with increased morbidity and mortality. Inflammation and oxidative stress play critical roles in AF occurrence and its complications. Therefore, evaluating the circulating levels of inflammatory and oxidative stress biomarkers and their possible applications in AF diagnosis and management have been the focus of many efforts. The monocyte-to-high-density lipoprotein cholesterol ratio (MHR) and neutrophil-to-lymphocyte ratio (NLR) are two non-invasive, available, and established markers that serve as indicators of inflammation and oxidative stress. This review summarizes the current literature regarding alterations in the NLR, MHR, and other composite markers of systemic inflammation in AF patients. Moreover, this review discusses the clinical performance of these markers in predicting AF occurrence, recurrence, and disease outcomes. The PubMed, Scopus, and ScienceDirect online databases were searched for relevant studies using appropriate keywords, including "atrial fibrillation", "monocyte to high-density lipoprotein cholesterol ratio", and "neutrophil to lymphocyte ratio". The results of this review revealed the association of elevated levels of systemic inflammatory markers, specifically the NLR and MHR with AF and its complications. This finding indicates the potential role of subclinical inflammation in the development of AF, emphasizing its consideration in both the prevention and treatment of AF and associated complications. Despite these promising findings, the utilization of these markers in routine clinical settings faces challenges, including low specificity and sensitivity and varying cut-off values across different studies.