Background/Purpose: Cardiovascular disease is an important contributor to mortality in Systemic Lupus Erythematosus (SLE). It has been reported that disease activity at diagnosis was associated with the occurrence of myocarditis and coronary artery disease (CAD) in SLE. Fragmented QRS (fQRS) is a convenient marker of myocardial scar by electrocardiogram (ECG) defined as additional spikes within the QRS complex. FQRS is useful for identification of myocardial scars such as CAD and cardiac sarcoidosis, and for identifying high-risk patients of various cardiac diseases. It has reported that the prevalence of fQRS in a patient with SLE appears to be higher than that in controls. However, no clinical studies have investigated the prevalence at the time of diagnosis. In addition, there is no report that examined the association of disease activity of SLE and fQRS. In this study, we aimed to assess the relationship between disease activity of SLE and fQRS in SLE patients at the time of diagnosis. We hypothesized that the frequency of fQRS on ECGs would be higher in SLE patients with high disease activity.

Methods: The study design was a cross-sectional study. The participants were SLE patients who diagnosed at Showa University Hospital and Showa University Koto Toyosu Hospital from January 2010 to December 2017. The participants who satisfied American College of Rheumatology criteria were included. The patients with cardiac disease, other rheumatic diseases, and already treatment at the time of an ECG measurement were excluded. The exposure was the appearance of fQRS. All ECGs were evaluated by two experienced cardiologist blinded for patient characteristics. The primary outcome was Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K). The secondary outcomes were the complement level and the anti-dsDNA antibody level. In the main analysis, a multiple regression analysis was conducted to assess the association between fQRS and SLE activity adjusted for age, sex and period from the estimated date of onset to the date of diagnosis. In the secondary analysis, a multiple regression analysis was conducted to analysis the association between fQRS and the serological activity of SLE (the complement level, the anti-dsDNA antibody level) under the same conditions as above. Interobserver variabilities were assessed using Cohen’s kappa coefficient.

Results: In total, 45 participants were enrolled. The mean age was 42.3 years, and 37 (82%) were female. The median SLEDAI-2K was 14 [IQR, 10 to 20]. The median period from the estimated date of onset to the date of diagnosis was 3 months [IQR, 2 to 14.5]. 25 patients (56%) had fQRS. In the main analysis, the regression coefficients [95%CI] of fQRS for SLEDAI were 2.99 [1.15 to 4.84, p=0.002] with reference to non-fQRS. In the secondary analysis, there were no significant associations between fQRS and the blood test. There was a good agreement between two blinded experienced cardiologists reading of fQRS. There was a 91.1% consensus (κ=0.81, 95% CI 0.63 to 0.98, p<0.001).

Conclusion: Our results demonstrated that fQRS positive SLE patients tended to have high disease activity. It was suggested that fQRS could be expressed by myocardial scar in SLE cases with high disease activity.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/fragmented-qrs-in-patients-with-systemic-lupus-erythematosus-relation-to-the-disease-activity-a-cross-sectional-study/