Background: Heart rate (HR) reduction is associated with improved outcomes in patients with heart failure (HF) and biomarkers can be a valuable diagnostic tool in HF management. The primary aim of our study was to evaluate the short-term (6 months) effect of ivabradine on N-terminal pro B-type natriuretic peptide (NT-proBNP), CA-125, and cystatin-C values in systolic HF outpatients, and secondary aim was to determine the relationship between baseline HR and the NT-proBNP, CA-125, cystatin-C, and clinical status variation with ivabradine therapy.

Methods: Ninety-eight patients (mean age: 65.81 ± 10.20 years; 33 men), left ventricular ejection fraction < 35% with Simpson method, New York Heart Association (NYHA) class II–III, sinus rhythm and resting HR > 70/min, optimally treated before the study were included. Among them, two matched groups were formed: the ivabradine group and the control group. Patients received ivabradine with an average (range of 10–15) mg/day during 6 months of follow-up. Blood samples for NT-proBNP, CA-125, and cystatin-C were taken at baseline and at the end of a 6-month follow-up in both groups.

Results: There was a significant decrease in NYHA class in the ivabradine group (2.67 ± ± 0.47 vs. 1.85 ± 0.61, p < 0.001). When ivabradine and control groups were compared, a significant difference was also found in NHYA class 6 months later (p = 0.013). A significant decrease was found in HR in the ivabradine and control groups (84.10 ± 8.76 vs. 68.36 ± ± 8.32 bpm, p = 0.001; 84.51 ± 10 vs. 80.40 ± 8.3 bpm, p = 0.001). When both groups were compared, a significant difference was also found in HR after 6 months (p = 0.001). A significant decrease was found in cystatin-C (2.10 ± 0.73 vs. 1.50 ± 0.44 mg/L, p < 0.001), CA-125 (30.09 ± 21.08 vs. 13.22 ± 8.51 U/mL, p < 0.001), and NT-proBNP (1,353.02 ± 1,453.77 vs. 717.81 ± 834.76 pg/mL, p < 0.001) in the ivabradine group. When ivabradine and control groups were compared after 6 months, a significant decrease was found in all HF parameters (respectively; cystatin-C: p = 0.001, CA-125: p = 0.001, NT-proBNP: p = 0.001). Creatinine level was significantly decreased and glomerular filtration rate (GFR) was significantly increased in the ivabradine group (1.02 ± 0.26 vs. 0.86 ± 0.17, creatinine: p = 0.001; 79.26 ± 18.58 vs. 92.48 ± 19.88, GFR: p = 0.001). There was no significant correlation between NYHA classes (before and after ivabradine therapy) and biochemical markers, or HR.

Conclusions: In the outpatients with systolic HF, persistent resting HF > 70/min with optimal medical therapy, the NT-proBNP, CA-125, and cystatin-C reductions were obtained with ivabradine treatment. Measurement of NT-proBNP, CA-125, and cystatin-C may prove to be useful in biomarker panels evaluating ivabradine therapy response in HF patients.