Background: Patients with systemic lupus erythematosus (SLE) have an increased risk of developing cardiovascular illnesses. Asymptomatic affection might exist, so early diagnosis can improve the outcome. Aim: The purpose of this study was to determine the importance of highly sensitive C-reactive protein, fragmented QRS, and fibrinogen levels in identifying subclinical cardiac involvement in SLE patients, as well as how these variables relate to disease activity. Results: Regarding hs-CRP and fibrinogen, there were significant differences between the SLE and control group, with a higher frequency of fQRS in the lupus group. The lupus group was divided into 2 subgroups: 44 patients with fragmented QRS in ECG (83%) and 9 patients with normal QRS (17%) with a higher mean value of hs-CRP and fibrinogen level (58.76 ± 70.15, 18.54 ± 26.79) and low HDL (53.37 ± 10.37) in those with fQRS (+). The sensitivity and specificity of hs-CRP at a cut of level (3.5 mg/L) for fQRS in SLE patients were 75.5%, and 71.7%, respectively. Regression analysis showed hs-CRP and were significant predictors for fQRS changes in SLE patients. Conclusions: A more thorough evaluation of SLE patients with fQRS complexes with hs-CRP and fibrinogen is important with close follow-up for the detection of subclinical cardiac involvement in SLE. Also, SLE activity is linked to fQRS and fibrinogen. Therefore, we advise using them for additional medical care for lupus. Key points • Subclinical cardiac involvement in SLE patients. • Fragmented QRS and fibrinogen associated with SLE activity. Keywords SLE, Fragmented QRS complex, Hs-CRP, Fibrinogen, Asymptomatic cardiac.