title: Long-term prognostic value of time domain analysis of signal-averaged electrocardiography in idiopathic dilated cardiomyopathy.
abstract: The aim of this study was to evaluate the long-term prognostic value of signal-averaged electrocardiography (SAECG) in idiopathic dilated cardiomyopathy (IDC). Time domain analysis of SAECG was assessed in 131 patients with angiographically confirmed IDC (age 52+/-12 years; 108 men; left ventricular ejection fraction 33+/-12%) using specific criteria in 44 patients with bundle branch block. Late potentials (LP) on SAECG were present in 27% of the patients. Patients with LP had a similar left ventricular ejection fraction and a similar left ventricular end-diastolic diameter than patients with a normal SAECG. With a follow-up of 54+/-41 months, 24 patients suffered cardiac death and 19 had major arrhythmic events (sudden death, resuscitated ventricular fibrillation, or sustained ventricular tachycardia). Patients with LP had an increased risk of all-cause cardiac death (RR 3.3, 95% confidence interval 1.5 to 7.5, p = 0.004) and of arrhythmic events (RR 7.2, 95% confidence interval 2.6 to 19.4, p = 0.0001). Using multivariate analysis, only LP on SAECG (p = 0.001), reduced SD of all normal-to-normal intervals (SDNN) (p = 0.002), increased pulmonary capillary wedge pressure (p = 0.005), and history of sustained ventricular tachyarrhythmia (p = 0.02) predicted cardiac death. A history of previous sustained ventricular tachyarrhythmia (p = 0.0001), reduced SDNN (p = 0.003), and LP on SAECG (p = 0.006) were the only independent predictors of major arrhythmic events. Results were not altered when considering separately patients with or without bundle branch block, or after exclusion of patients with a history of sustained ventricular tachyarrhythmia. This study is one of the first to suggest that LP on SAECG is an independent predictor of all-cause cardiac death and is of high interest for arrhythmia risk stratification in IDC.
authors.affiliation: Service de Cardiologie B et Laboratoire d'electrophysiologie cardiaque, Centre Hospitalier Universitaire Trousseau, Tours, France. lfau@med.univ-tours.fr
authors.forename: L
authors.initials: L
authors.lastname: Fauchier
authors.forename: D
authors.initials: D
authors.lastname: Babuty
authors.forename: P
authors.initials: P
authors.lastname: Cosnay
authors.forename: P
authors.initials: P
authors.lastname: Poret
authors.forename: P
authors.initials: P
authors.lastname: Rouesnel
authors.forename: J P
authors.initials: JP
authors.lastname: Fauchier
mesh_terms: D001145:Arrhythmias, Cardiac / Q000453:epidemiology; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis* / Q000401:mortality; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D004562:Electrocardiography / Q000379:methods*; D015716:Electrocardiography, Ambulatory / Q000379:methods; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D018570:Risk Assessment; D012815:Signal Processing, Computer-Assisted; D016019:Survival Analysis; D013997:Time Factors