Systemic immune-inflammatory index and other inflammatory markers in electrical storm vs. patients undergoing elective ventricular tachycardia ablation

Ventricular arrhythmias (VA) are a major cause of sudden cardiac death (SCD) in heart failure patients. It is not known whether readily available clinical markers are of any clinical yield in detecting a subclinical inflammation that may be inflicted in acute arrhythmogenesis. This study aimed to evaluate the prognostic value of inflammatory markers in patients undergoing ventricular tachycardia (VT) catheter ablation and to compare characteristics between those with electrical storm (ES) and elective ablation (EL). This retrospective observational study included patients with structural heart disease undergoing VT ablation. Inflammatory markers (CRP, blood leukocyte, neutrophil, platelet, lymphocyte counts and systemic immune-inflammatory index (SII)) were assessed pre-procedurally. We analyzed procedural outcomes, VT recurrence, mid-term mortality and the presence of an electrical storm, correlating these with inflammatory markers. <i>p</i> &lt; 0.05 was considered significant in all analyses. Of the 140 patients analyzed (median age 65 ± 15 years; 87.1% males), 63 (45%) had ES and 77 (55%) underwent elective ablation. The median ejection fraction was 25% ±15. The ES group had significantly higher neutrophil counts and systemic immune-inflammation index (SII) compared to the EL group (<i>p</i> = 0.010 and <i>p</i> = 0.013, respectively). On univariate analysis, elevated SII was associated with mid-term mortality (HR 3.487, <i>p</i> = 0.016), alongside age &gt; 70 years and history of coronary artery bypass grafting (CABG). SII and history of CABG were independent predictors of death on multivariate analysis (HR 1.879, <i>p</i> = 0.018) and (HR: 4.891, <i>p</i> = 0.003), respectively. SII is notably higher in those experiencing ES and is a predictor of mid-term mortality.