Abstract 4147891: The neutrophil-to-lymphocyte ratio as a novel predictor of idiopathic left ventricular versus right outflow tract premature ventricular contractions.

Background: The pathogenesis of idiopathic premature ventricular contractions (PVCs) may differ between patients with left- vs right- outflow tract (LVOT; RVOT) PVCs. We hypothesized that PVCs of LVOT origin would be associated with a higher prevalence of inflammatory conditions, such as coronary artery disease (CAD) and aortic sclerosis (AS), and elevation in the inflammatory biomarker, neutrophil-to-lymphocyte ratio (NLR). Research Question: Is NLR associated with LVOT PVCs? Aim: To compare clinical factors and NLR between patients with left- versus right-outflow tract origin of PVCs. Methods: We studied 140 patients undergoing idiopathic outflow tract PVC ablations at our institution. Patients with acute inflammatory conditions were excluded. NLR was calculated by dividing the absolute neutrophil by lymphocyte counts. Associations between clinical variables, NLR, and PVC site of origin at ablation were examined using logistic regression analysis. Results: An LVOT site of origin was present in 48 (35%) patients, with significant differences in clinical variables to RVOT patients. Independent predictors of LVOT (vs RVOT) PVCs were chronic kidney disease (CKD, odds ratio [OR]: 5.3, 95% CI: 1.3 - 22.1), age>50 (3.8, 1.6 - 8.6) and NLR (1.35, 0.9 - 1.9). An elevated NLR (≥3.92) was present in 14% of patients with LVOT PVCs vs 6.4% in those with RVOT PVCs (p<0.006). Conclusions: We found a significant difference in risk factors between otherwise idiopathic LVOT vs RVOT PVCs. In contrast to those with RVOT PVCs, patients with PVCs of LVOT origin are older and have a higher prevalence of CKD. NLR is an independent predictor for LVOT PVCs. Our findings highlight the potential importance of inflammation as a selective mediator of LVOT PVCs.