Evaluation of Fragmented QRS complex and conduction abnormalities and its association with disease severity in systemic sclerosis patients, a case-control study

Systemic Sclerosis (SSc) is an autoimmune disease with multi-organ involvement mostly due to fibrosis and ectopic or excessive collagen fibers production in organs. Myocardial fibrosis is the main finding of cardiac involvement in patients with systemic sclerosis. In recent studies, the presence of Fragmented QRS complexes (FQRS) has been shown in the surface electrocardiogram in relation to fibrosis.

The present study is a case-control study during March 2019 to February 2020 that was conducted in 148 patients with scleroderma referred to the Rheumatology clinic in Shariati Hospital and 101 non-ischemic individuals in the control group matched by age and sex with the patient group. All the medical records were reviewed and those who were low risk according to 10-year atherosclerotic cardiovascular disease (ASCVD) risk assessment were selected as case groups. Data of ECG were evaluated for availability of FQRS or conductive abnormalities and calculating PR, QRS, QT, QTc and Tp-e intervals.

Of the 141 patients with systemic sclerosis, 127(85.81%) were female and 21(14.19%) were male. In the control group, 81 women (80.2%) were present. 61(41.2%) of patients with scleroderma and 8(7.9%) of the control group in this study had FQRS changes in their electrocardiogram. In this study, QRS, QTc and Tp-e intervals were significantly higher in patients with systemic sclerosis compared to those in the control group. The frequency of FQRS, LAHB and LPHB in patients with systemic sclerosis was significantly more than control group. The relationship between PR, QRS, QTc, Tp-e intervals with age, length of disease onset and the severity of skin involvement was assessed. There was a significant correlation between PR-interval and age. Furthermore, there were a correlation between QRS interval and Rodnan skin score, Pulmonary Artery Pressure and Finger to Palm. It is also a meaningful correlation between QTc interval and Rodnan score.

The FQRS finding in electrocardiogram in patients with systemic sclerosis, which has no obvious cardiac symptoms, may indicate myocardial fibrosis and predict future cardiac disorders.