Adult heart block is associated with disease activity in primary Sjögren's syndrome

Objectives: Congenital heart block occurring in the foetus and neonate may be associated with maternal anti-SS-A/anti-SS-B autoantibodies (anti-SSA/anti-SSB). The adult atrioventricular node is generally thought to be resistant to the damaging effects of anti-SSA/anti-SSB. However, case reports suggest that heart block developing in adult Sjögren's syndrome (SS) patients may be associated with these autoantibodies. Therefore, we investigated the relationship between serum antibodies and heart block in adult SS patients. Methods: We abstracted data from clinic patient records. Diagnosis of primary SS was based on American-European classification criteria. Electrocardiograms (EKGs), laboratory immunology parameters, lipid profiles, and focus scores from labial salivary gland biopsies were available for 51 SS patients. Fifteen patients had follow-up EKGs. PR interval≥200 ms was considered to be first-degree heart block. Results: Five patients showed prolonged PR intervals; the presence of heart block was not related to the presence of anti-SSA antibodies. However, significant differences between patients with prolonged and normal PR intervals were seen for mean focus scores (p < 0.0001), anti-cardiolipin immunoglobulin IgG (p=0.0009), age (p=0.01), IgG (p=0.02), anti-SSB antibodies (p=0.02), and high density lipoprotein (HDL) cholesterol levels (p=0.03). These parameters correlated with prolonged PR intervals. Conclusions: These results suggest an association between disease activity, the presence of anti-SSB antibodies, and the occurrence of first-degree heart block in adults with primary SS.