Limited Utility of Screening Electrocardiograms in Systemic Sclerosis: Data from the Canadian Scleroderma Research Group

OBJECTIVE: Recommendations have been made to use electrocardiograms (EKGs) to screen for cardiac disease in systemic sclerosis (SSc). The objective of this study was to compare the prevalence of EKG abnormalities in SSc and controls to help determine if the EKG should be used as a screening tool. METHODS: EKGs from patients with SSc were compared with those from a random sample of age- and gender-matched controls. Two cardiologists read all EKGs using a standardized approach. The groups were compared using t-tests, chi-squared tests, and Fisher exact tests. RESULTS: Patients with SSc (n = 833, mean ± SD disease duration 11.3 ± 9.3 years; 39.4% had diffuse cutaneous SSc) and controls (n = 832) were included. The prevalence of conduction and rhythm abnormalities were similar in the SSc and control groups. More patients with SSc than controls had possible right atrial enlargement (5% vs 0.1%, P < 0.001), right axis deviation (3.2% vs 0.4%, P < 0.001), left atrial enlargement (9.2% vs 1.6%, P < 0.001), poor/abnormal R progression (5.6% vs 2.2%, P < 0.001) and nonspecific T wave abnormalities (6.1% vs 3.4%, P = 0.008). CONCLUSION: Our findings suggest that conduction abnormalities are not more prevalent in those with SSc than in controls. Evidence of right heart stress on EKG in SSc may be secondary to pulmonary hypertension and left atrial enlargement, and poor R wave progression in precordial leads may indicate myocardial damage. Future studies are required to determine if these EKG abnormalities represent underlying structural heart disease, and, until that is proven, EKGs should not be considered a screening tool for cardiac abnormalities in SSc.