Association of post-cardioversion transcardiac concentration gradient of soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) and inflammatory biomarkers to atrial fibrillation recurrence.

Objectives: Soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) has been shown to have both pro- and anti-apoptotic activities and is associated to better prognosis in heart failure. The aim of this study was to determine the transcardiac concentration gradient of sTRAIL and inflammatory biomarkers after AF cardioversion and assess their relation to AF recurrence.

Design And Methods: We measured transcardiac gradients (coronary sinus concentration minus aortic root concentration) of sTRAIL, C-reactive protein (hsCRP) and interleukin-6 (IL-6) in patients with non-valvular AF after electrical cardioversion. Six-month AF recurrence was the study endpoint.

Results: There were no differences in sTRAIL and hsCRP concentrations in peripheral venous blood between patients with and without AF recurrence (p=0.066 and 0.149, respectively), while IL-6 was higher in patients with recurrence (p=0.032). Only sTRAIL showed a significant transcardiac gradient [3 pg/mL (IQR 1-4 pg/mL); p=0.01]. sTRAIL gradient was 4 pg/mL (IQR 3-5 pg/mL) in patients without recurrence versus -1 pg/mL (IQR -2-1 pg/mL) in those with recurrence (p<0.001). IL-6 (p=0.281) and hsCRP (p=0.979) aortic concentrations were not significantly different from coronary sinus concentrations. In multivariate analysis, sTRAIL transcardiac gradient (beta -0.81, p=0.004) remained a negative predictor of AF recurrence.

Conclusion: This study demonstrates the existence of a significant transcardiac sTRAIL concentration gradient in patients with non-valvular AF, inversely associated to AF recurrence. These results suggest production of sTRAIL by the heart and a protective role against substrate-altering processes in AF-prone atria. This could have implications for TRAIL-targeting therapies currently under development.