Prevalence and clinical significance of electrocardiographic signs of atrial myopathy in rheumatoid arthritis: results from the EDRA study

Objective We sought to determine whether the increased risk of atrial fibrillation and stroke in rheumatoid arthritis (RA) can be accounted for by an increased prevalence of electrocardiographic markers of atrial myopathy. Methods We retrospectively evaluated clinical and electrocardiographic data of 218 RA patients prospectively enrolled in the Endothelial Dysfunction Evaluation for Coronary Heart Disease Risk Estimation in Rheumatoid Arthritis study (EDRA study ClinicalTrials.gov: NCT02341066) and 109 controls matched by age and gender. The prevalence of interatrial blocks (IAB, partial – pIAB or advanced - aIAB), abnormal P-wave terminal force in lead V ₁ (aPtfV ₁) and atrial myopathy (electrocardiographically defined as the presence of 1) aIAB, or 2) pIAB plus abnormal aPtfV ₁) was assessed in each group. RA patients were followed-up for 5 years for incident atrial fibrillation and cardiovascular events. Results Barring the prevalence of hyperlipidaemia and obesity, the demographic characteristics and cardiovascular risk profile of RA patients and controls were comparable. All subjects enrolled in the study were free from previous cardiovascular disease and atrial fibrillation. Compared to controls, RA patients had longer P-wave duration (118±12 vs. 112±10 ms, p<0.001) and higher prevalence of pIAB (43% vs. 21%, p<0.001) and abnormal PtfV ₁ (27% vs. 10%, p<0.001). Accordingly, atrial myopathy was significantly more prevalent (15% vs 4%, p=0.003) in RA patients. In multiple regression, male gender (OR [95% CI] = 3.09 [1.48–6.47], p=0.003) and RA (OR [95% CI] = 4.83 [1.58–14.73], p=0.006) were independently associated with atrial myopathy. Atrial myopathy was not significantly associated with incident atrial fibrillation or cardiovascular events in RA patients after 5 years of follow-up. Conclusion Electrocardiographic markers of atrial myopathy are independently associated with RA. Further studies with larger sample size and longer follow-up are needed to determine whether the increased prevalence of atrial myopathy contributes to the increased risk of atrial fibrillation and stroke in this group.