Plasma YKL-40, a new biomarker for atrial fibrillation?

Aims The aim of this study was to determine changes in a new potential biomarker plasma YKL-40 in patients with atrial fibrillation (AF) before and after electrical cardioversion (CV). Methods and results Plasma concentrations of YKL-40 were measured in 56 patients (mean age 65 years, range 34-84) with persistent AF (lasting mean 128 days, range 14-960), in 19 age-matched patients with permanent AF, and in 19 healthy subjects. The patients with persistent AF underwent CV. Plasma YKL-40 was measured prior to CV, and at follow-up after 24 h, 30 and 180 days. Patients with persistent AF had lower plasma YKL-40 than patients with permanent AF [70 mu g/L (42-105)] vs. [138 mg/L (48-225)] (P = 0.003), and higher levels than healthy subjects [41 mu g/L (29-52)] (P = 0.001). Patients (n = 22) who were still in sinus rhythm (SR) at follow-up 30 days after CV had unchanged plasma YKL-40 compared with baseline levels. The baseline levels of YKL-40 were correlated to the levels of IL-6, but not to high sensitivity C-reactive protein. Conclusion Patients with AF have significantly elevated levels of YKL-40. YKL-40 was not a significant predictor of successful CV to SR. Plasma levels of YKL-40 did not fall after restoration of SR.