The Importance of Nitric Oxide and Oxidative Stress in Atrial High-Rate Episodes in Patients with Cardiac Devices

Objective: Atrial High Rate Episodes (AHRE) are subclinical atrial tachyarrhythmias detectable by cardiac implantable electronic devices (CIEDs). AHREs have been associated with an increased risk of developing atrial fibrillation (AF), thromboembolism, cardiovascular and cerebrovascular events, and mortality. Although recent studies have assessed the value of oxidative stress markers in patients with AF, the relationships between AHRE and oxidative stress markers, including nitric oxide, has not yet been elucidated. This study aims to investigate the relationship between these markers and AHRE.
Method: This prospective, cross-sectional study comprised 180 patients with CIEDs. The study population was divided into two groups based on the presence (n = 78) and absense (n = 102) of AHRE to analyze its association with biomarkers.
Results: The AHRE (+) group was significantly older, had a higher prevalence of hypertension, higher NT-proBNP (508.8 +/- 249 pg/mL vs. 415.3 +/- 292.1; P = 0.037), malondialdehyde (MDA) levels (20.9 +/- 4.1 pmol/L vs. 19.1 +/- 3.1 pmol/L; P = 0.006), and inducible nitric oxide synthase (iNOS) activity (1,935.9 +/- 326.1 pg/mL vs. 1,677.4 +/- 363.2 pg/mL; P < 0.001). Logistic regression analysis identified age, hypertension, MDA (odds ratio [OR]: 1.131, 95%CI: 1.009 - 1.268, P 0.035), iNOS activity (OR = 1.002, 95% CI = 1.001 - 1.003, P < 0.001), and endothelial nitric oxide synthase (eNOS) activity (OR = 0.990, 95% CI = 0.986 - 0.984, P < 0.001) as independent predictors of AHRE.
Conclusion: The study findings indicated that plasma levels of NT-proBNP, MDA, nitric oxide, and the expression of iNOS and eNOS were significantly associated with AHRE. Moreover, elevated plasma MDA concentrations, increased iNOS activity, and decreased eNOS activity were identified as independent predictors of AHRE.