Anti-Ro antibodies and complete heart block in adults with Sjögren's syndrome

There are emerging case reports worldwide of complete heart block in adults who test positive for anti-Ro antibodies and the underlying primary Sjögren's syndrome (pSS). The association between fetal/congenital cardiac abnormalities and transplacental transfer of anti-Ro antibodies is well established; there is, however, an ongoing debate about the underlying mechanism of activity of these antibodies in the cardiac tissue. In the past, maternal cardiac tissue was believed to be resistant to these pathogenic effects. This case highlights the need to change our understanding of how these antibodies cause adverse arrhythmogenic cardiac effects in adults. We present the case of a 44-year-old female with pSS and positive anti-Ro autoantibodies, who was diagnosed with autoimmune-induced complete heart block after presenting with dizziness and palpitations. She required insertion of a permanent cardiac pacemaker and has made a full recovery. Although the arrhythmogenic effects are rare, it may be that cardiac conduction in adults is not as resistant to anti-Ro antibodies as proposed.