NVAF is generally believed to be an inflammatory disease process. sCD40L represents a sensitive in vivo indicator of platelet activation and may serve as an “inflammatory and thrombotic thermometer.”
Plasma sCD40L was measured using enzyme-linked immunoadsorbent assay in 109 NVAF cases (60.9 ± 15 years of age; 26% women) and 48 normal sinus rhythm (NSR) controls (62.3 ± 15 years of age; 44% women). Patients were separated by arrhythmia duration of <1 month (n = 21), 1 to 12 months (n = 18), and >12 months (n = 70).
Median sCD40L level was significantly higher in NVAF cases than in NSR controls (321 pg/ml vs. 238 pg/ml, respectively; p = 0.029). This difference was driven by higher levels in patients with NVAF duration for <1 month (552 pg/ml) and 1 to 12 months (328 pg/ml). NVAF patients with arrhythmia duration for over 1 year had sCD40L levels not significantly different from those of NSR controls. An sCD40L concentration of 552 pg/ml distinguished NVAF patients with dysrhythmia duration of <1 month (area under the curve [AUC] of 0.72; p = 0.0010) or duration for ≤12 months (AUC: 0.69; p = 0.0003) from NSR controls. Circulating sCD40L levels were also significantly higher among patients with mild spontaneous echocardiogram contrast (SEC) (p = 0.0378) and those with moderate SEC (p = 0.007) compared with NSR controls.
sCD40L levels are significantly higher in NVAF patients than in NSR controls but only for up to 1 year after development of dysrhythmia. An sCD40L concentration of 552 pg/ml can help to assess development or recurrence of asymptomatic NVAF.