Elevated calprotectin in patients with atrial fibrillation with and without heart failure

Calprotectin is an inflammatory marker, which has been found elevated in patients suffering from cardiac conditions, e.g. myocardial infarction, unstable angina and chronic heart failure. Inflammation has further been linked to atrial fibrillation (AF). However, the association between calprotectin and AF is unknown. We aimed to compare calprotectin levels in patients suffering from AF with healthy adults. In addition, AF patients with and without heart failure were compared. Calprotectin was measured in patients undergoing elective direct current cardioversion for AF. Calprotectin was determined before, 4 hours and 3 months after cardioversion. Healthy blood donors were used to verify the reference interval for calprotectin. In total, 104 prospectively enrolled patients were included. The median serum calprotectin level for AF patients was 1.6 μg/mL before cardioversion. Calprotectin levels increased significantly 4 h (1.9 μg/mL) and 3 months (2.2 μg/mL) after cardioversion. Blood donors' median serum calprotectin (1.3 μg/mL) was significantly lower than AF patients. AF patients with heart failure had significantly higher calprotectin at baseline compared with AF patients without a history of heart failure (2.0 μg/mL vs. 1.5 μg/mL). The difference was not significant at 4 h (2.0 μg/mL vs. 1.7 μg/mL) or 3 months (2.5 μg/mL vs. 2.2 μg/mL). In conclusion, the calprotectin levels in patients with AF were significantly higher than healthy blood donors and were further increased after cardioversion. AF patients with heart failure had significantly higher levels of calprotectin than AF patients without heart failure.