The association between cardiac arrhythmia and autoantibodies in systemic sclerosis.

OBJECTIVE: This study aimed to investigate the association between specific autoantibodies and cardiac arrhythmias in Japanese patients with systemic sclerosis (SSc). METHODS: 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. RESULTS: 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. CONCLUSION: Distinct SSc-related autoantibodies were differentially associated with the occurrence of arrhythmias, suggesting that autoantibody profiles influence arrhythmic risk in SSc.