Approximately 1 in 4 patients with systemic lupus erythematosus (SLE) included in a recent study had resting specific electrocardiogram (ECG) abnormalities that predict future cardiovascular events, including myocardial infarction, sudden death, and congestive heart failure (Al Rayes H, et al. Arthritis Res Ther. 2017;19:31).
This study showed that older age, active SLE, and SLE-related damage were associated with the presence of ECG-4 and ECG-5 abnormalities, whereas treatment of hyperlipidemia was found to be protective.
“These findings of the high prevalence of ECG-4 and ECG-5 abnormalities in this study of SLE patients without documented CVD [cardiovascular disease] suggest that baseline, and possibly follow-up sequential, ECG may be a useful noninvasive SLE screening tool for identification of SLE patients at increased risk for CVD. The finding that active SLE disease and damage were associated with these abnormalities underscores the importance of controlling SLE disease activity,” noted lead investigator Hanan Al Rayes, MD, Lupus Clinic, Toronto Western Hospital, University of Toronto, Canada.
Although SLE has been established as an independent risk factor for CVD, these findings support early identification of resting ECG abnormalities in patients with the disease to improve risk stratification and management.
“Lupus patients are at an increased risk for cardiovascular events [eg, coronary heart disease, myocardial infarction] even in the absence of traditional risk factors for CVD. In addition, lupus was incorporated into the American Heart Association guidelines for the prevention of CVD in women. Thus, early identification of patients at an increased risk for CVD is crucial to the development and implementation of effective prevention strategies. Specific ECG abnormalities (ECG-CVD abnormalities) detected on resting ECG in healthy adults are associated with an increased risk for subsequent CVD events,” Dr Al Rayes noted.
The present study builds on previous findings. In 2011, Chou and colleagues demonstrated that ECG-CVD abnormalities, specifically ECG-4 elements (ie, ST segment and/or T-wave abnormalities, left ventricular hypertrophy, left axis deviation, left bundle branch block and right bundle branch block) are associated with subsequent CVD events in healthy adults.
“Ours is the first study to demonstrate that the prevalence of ECG-4 among SLE patients without documented CVD disease (21.4%) is greater than in the general population [prevalence 3.6%-17%]. Lupus patients with these abnormalities are younger than those in the general population. In our study, the prevalence of ECG-5 elements [any of the ECG-4 or pathological Q wave] was 24.2%,” she stated.Study Design
The study included 487 patients with SLE seen at the Toronto SLE clinic from October 2011 to November 2015. A 12-lead resting supine ECG was performed on each patient, and a cardiologist interpreted the ECGs. Patients with a history of CVD were excluded before undergoing an ECG.
CVD abnormalities were defined as the presence of ≥1 of the ECG-4 abnormalities. ECG-5 abnormalities included those of ECG-4 as well as Q-wave abnormality.
A total of 487 ECGs were evaluated, of which 314 (64.4%) patients had a normal ECG. ECG-4 abnormalities were detected in 104 (21.4%) patients and ECG-5 in 118 (24.2%) patients.
A multivariate analysis showed that older age (P = .002), active SLE disease, and disease damage (P = .009 and P = .002, respectively) were significantly associated with ECG-4 abnormalities. Statin treatment for hyperlipidemia was protective against ECG-4 (P = .02). The multivariate analysis for ECG-5 showed similar associations.
A trend was observed for an association between immunosuppressive therapy and ECG-4, but this could be explained by the use of immunosuppressive therapy for patients with active disease.
In this study, traditional CVD risk factors, including smoking, hypertension, and diabetes, were not significantly associated with ECG abnormalities.
The study was limited by the lack of a control group and the absence of a baseline ECG for each patient, Dr Al Rayes and colleagues noted. However, despite the limitations of the study, they believe that early identification of patients with SLE at increased risk for premature CVD is critical to the development and implementation of effective preventive strategies in this population. The investigators also asserted that prospective studies of targeted CVD prevention strategies are needed in patients with SLE with ECG-4 and ECG-5 abnormalities.