The association between cardiac arrhythmia and autoantibodies in systemic sclerosis

This study aimed to investigate the association between specific autoantibodies and cardiac arrhythmias in Japanese patients with systemic sclerosis (SSc).

Arrhythmias of patients with SSc treated at Kyoto University Hospital were retrospectively analyzed, focusing on anti-topoisomerase I antibody (ATA), anti-centromere antibody (ACA), anti-RNA polymerase III (RNAPIII), and anti-U1-ribonucleoprotein (RNP). Logistic regression analyses were performed to assess the relationships between autoantibodies and arrhythmias.

Cardiac arrhythmias were observed in 153 of 389 SSc patients (39%), including premature atrial contraction (PAC, 25.2%), premature ventricular contraction (PVC, 23.9%), atrial fibrillation (AF, 4.6%), atrial tachycardia/atrial flutter (AT/AFL, 1.5%), ventricular tachycardia/ventricular fibrillation (VT/VF, 0.3%), bradyarrhythmia (5.9%), and pacemaker implantation (1.5%) during 12.62±1.06-year observation periods. The highest frequency was observed in anti-RNAPIII (42.4%), followed by ATA (38.7%), ACA (35.8%), and anti-U1-RNP (30.0%). After age- and sex-adjustment, ACA was negatively associated with the occurrence of arrhythmia (odds ratio [OR]=0.51, P=0.007), especially PAC (OR=0.47, P=0.004) among patients with SSc. Conversely, anti-U1-RNP was positively associated with AF (OR=4.7, P=0.04). There were no significant differences in the frequencies of PVC, AT/AFL, VT/VF, or tachyarrhythmias overall among autoantibodies.

Distinct SSc-related autoantibodies were differentially associated with the occurrence of arrhythmias, suggesting that autoantibody profiles influence arrhythmic risk in SSc.