Prospective Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Cardiol. Jun 26, 2015; 7(6): 344-350
Published online Jun 26, 2015. doi: 10.4330/wjc.v7.i6.344
Utility of electrophysiological studies to predict arrhythmic events
Gabriela Hilfiker, Andreas W Schoenenberger, Paul Erne, Richard Kobza
Gabriela Hilfiker, Paul Erne, Richard Kobza, Division of Cardiology, Luzerner Kantonsspital, 6000 Luzern, Switzerland
Andreas W Schoenenberger, Division of Geriatrics, Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
Paul Erne, Hirslanden Klinik St Anna, 6006 Luzern, Switzerland
Author contributions: The authors contributed equally to this work.
Ethics approval: This study was reviewed and approved by the Swiss Ethics Committees on research involving humans in Lucerne, Switzerland.
Informed consent: All study participants, or their legal guardian, provided informed written consent prior to study enrollement.
Conflict-of-interest: No conflict of interest.
Data sharing: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Richard Kobza, MD, Division of Cardiology, Luzerner Kantonsspital, Spitalstrasse, Luzern 16, 6000 Luzern, Switzerland. richard.kobza@luks.ch
Telephone: +41-41-2055208 Fax: +41-41-2055109
Received: September 11, 2014
Peer-review started: September 11, 2014
First decision: September 28, 2014
Revised: February 12, 2015
Accepted: April 10, 2015
Article in press: April 14, 2015
Published online: June 26, 2015
Processing time: 287 Days and 12 Hours
Abstract

AIM: 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.

CONCLUSION: EPS provides a benefit in risk stratification for future tachyarrhythmic events and SCD and should especially be considered in patients with LVEF ≥ 35%.

Keywords: Electrophysiologic techniques; Cardiac; Arrhythmia; Cardiac; Sudden cardiac death

Core tip: In our long-term prospective cohort study we could reveal several important findings about the prognostic value of programmed ventricular stimulation for risk stratification of sudden cardiac death (SCD). First, in a mixed population with different cardiac pathologies inducible sustained ventricular tachyarrhythmia during electrophysiological stimulation (EPS) identified those at higher risk for SCD or appropriate implantable cardioverter defibrillators (ICD) activation. Second, left ventricular ejection fraction (LVEF) < 35% was another independent predictor of SCD surrogate. Third, in patients with LVEF > 35% negative EPS had a high negative predictive value for SCD and ICD activation.