title: QT-interval parameters are increased in systemic lupus erythematosus patients.
abstract: Systemic lupus erythematosus (SLE) patients have increased cardiovascular morbidity and mortality. QT-interval parameters are presumed markers of cardiovascular risk and have not been previously evaluated in SLE. Standard 12-lead ECGs were obtained from 140 female SLE outpatients and 37 age and body mass index-matched controls. QT interval was measured in each lead and heart rate-corrected maximum QT-interval duration (QTcmax) and QT-interval dispersion (QTd) were calculated. Risk factors for cardiovascular disease and lupus clinical features, disease treatment, disease activity and damage index were recorded. SLE patients have increased QT-interval parameters when compared to controls (QTcmax: 427.91 +/- 31.53 ms(1/2) versus 410.05 +/- 15.45 ms(1/2), P < 0.001; QTd: 52.38 +/- 22.21 ms versus 37.12 +/- 12.88 ms, P < 0.001). These differences persisted after excluding those patients with arterial hypertension, diabetes and with ECG abnormalities (QTcmax: 419.90 +/- 28.78 ms(1/2) versus 409.15 +/- 15.85 ms(1/2), P = 0.041; QTd: 54.74 +/- 26.00 ms versus 37.96 +/- 13.05 ms, P = 0.001). Multivariate linear regression for factors associated with QTcmax selected the presence of electrocardiographic left ventricular hypertrophy (ECG-LVH) (P = 0.003), nonspecific ST-T-wave abnormalities (P = 0.022) and left atrial enlargement (P = 0.044). Multivariate associates with QTd were age (P = 0.018), ECG-LVH (P = 0.022) and ST-T abnormalities (P = 0.031). In conclusion, SLE patients have increased QT interval parameters when compared to controls. This prolongation may lead to an increased cardiovascular risk. This finding might be due to subclinical atherosclerotic cardiovascular disease.
authors.affiliation: Department of Internal Medicine, Clementino Fraga Filho University Hospital, Medical School, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. claudiacardoso@hucff.ufrj.br
authors.forename: C R L
authors.initials: CR
authors.lastname: Cardoso
authors.forename: M A O
authors.initials: MA
authors.lastname: Sales
authors.forename: J A S
authors.initials: JA
authors.lastname: Papi
authors.forename: G F
authors.initials: GF
authors.lastname: Salles
mesh_terms: D000328:Adult; D016279:Atrial Function, Left / Q000502:physiology; D004452:Echocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000209:etiology / Q000503:physiopathology; D008133:Long QT Syndrome / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D012307:Risk Factors