title: Utility of electrophysiological studies to predict arrhythmic events.
abstract: OBJECTIVE
  To evaluate the prognostic value of electrophysiological stimulation (EPS) in the risk stratification for tachyarrhythmic events and sudden cardiac death (SCD).
  
  
  METHODS
  We conducted a prospective cohort study and analyzed the long-term follow-up of 265 consecutive patients who underwent programmed ventricular stimulation at the Luzerner Kantonsspital (Lucerne, Switzerland) between October 2003 and April 2012. Patients underwent EPS for SCD risk evaluation because of structural or functional heart disease and/or electrical conduction abnormality and/or after syncope/cardiac arrest. EPS was considered abnormal, if a sustained ventricular tachycardia (VT) was inducible. The primary endpoint of the study was SCD or, in implanted patients, adequate ICD-activation.
  
  
  RESULTS
  During EPS, sustained VT was induced in 125 patients (47.2%) and non-sustained VT in 60 patients (22.6%); in 80 patients (30.2%) no arrhythmia could be induced. In our cohort, 153 patients (57.7%) underwent ICD implantation after the EPS. During follow-up (mean duration 4.8 ± 2.3 years), a primary endpoint event occurred in 49 patients (18.5%). The area under the receiver operating characteristic curve (AUROC) was 0.593 (95%CI: 0.515-0.670) for a left ventricular ejection fraction (LVEF) < 35% and 0.636 (95%CI: 0.563-0.709) for inducible sustained VT during EPS. The AUROC of EPS was higher in the subgroup of patients with LVEF ≥ 35% (0.681, 95%CI: 0.578-0.785). Cox regression analysis showed that both, sustained VT during EPS (HR: 2.26, 95%CI: 1.22-4.19, P = 0.009) and LVEF < 35% (HR: 2.00, 95%CI: 1.13-3.54, P = 0.018) were independent predictors of primary endpoint events.
  
  
  CONCLUSIONS
  EPS provides a benefit in risk stratification for future tachyarrhythmic events and SCD and should especially be considered in patients with LVEF ≥ 35%.
authors.affiliation: Gabriela Hilfiker, Paul Erne, Richard Kobza, Division of Cardiology, Luzerner Kantonsspital, 6000 Luzern, Switzerland.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Hilfiker
authors.affiliation: Gabriela Hilfiker, Paul Erne, Richard Kobza, Division of Cardiology, Luzerner Kantonsspital, 6000 Luzern, Switzerland.
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Schoenenberger
authors.affiliation: Gabriela Hilfiker, Paul Erne, Richard Kobza, Division of Cardiology, Luzerner Kantonsspital, 6000 Luzern, Switzerland.
authors.forename: Paul
authors.initials: P
authors.lastname: Erne
authors.affiliation: Gabriela Hilfiker, Paul Erne, Richard Kobza, Division of Cardiology, Luzerner Kantonsspital, 6000 Luzern, Switzerland.
authors.forename: Richard
authors.initials: R
authors.lastname: Kobza
keywords: Arrhythmia; Cardiac; Electrophysiologic techniques; Sudden cardiac death