Observational Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Cardiol. Nov 26, 2016; 8(11): 657-666
Published online Nov 26, 2016. doi: 10.4330/wjc.v8.i11.657
Riata silicone defibrillation lead with normal electrical measures at routine ambulatory check: The role of high-voltage shock testing
Elia De Maria, Ambra Borghi, Lorenzo Bonetti, Pier Luigi Fontana, Stefano Cappelli
Elia De Maria, Ambra Borghi, Lorenzo Bonetti, Pier Luigi Fontana, Stefano Cappelli, Cardiology Unit, Ramazzini Hospital, 41012 Carpi (Modena), Italy
Author contributions: De Maria E contributed to concept design, data analysis/interpretation, drafting the article, critical revision, approval, statistics and data collection; Borghi A, Bonetti L, Fontana PL, Cappelli S contributed to drafting the article, critical revision, approval, statistics and data collection.
Institutional review board statement: The study was approved by the Institutional Board of our Department (Ethical Committee of Modena Province, Italy).
Informed consent statement: Patient’s consent was obtained.
Conflict-of-interest statement: The authors report no relationships that could be construed as a conflict of interest.
Data sharing statement: Technical appendix, statistical code, dataset available from the corresponding author at e.demaria@inwind.it.
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: Elia De Maria, MD, PhD, Chief of Arrhythmology Lab, Cardiology Unit, Ramazzini Hospital, Via Molinari 1, 41012 Carpi (Modena), Italy. e.demaria@inwind.it
Telephone: +39-059-659320 Fax: +39-059-659387
Received: June 2, 2016
Peer-review started: June 4, 2016
First decision: July 5, 2016
Revised: July 21, 2016
Accepted: September 21, 2016
Article in press: September 22, 2016
Published online: November 26, 2016
Abstract
AIM

To describe our experience with shock testing for the evaluation of patients with Riata™ leads.

METHODS

Among 51 patients with normal baseline electrical parameters, 20 died during follow-up. Of the remaining 31 patients, 15 underwent the test: In 10 cases a defibrillation testing with ventricular fibrillation (VF) induction and in 5 cases a R-wave-synchronized shock (> 20 J, without inducing VF). The test was performed under sedation with Midazolam.

RESULTS

Twelve patients (80%) had a normal behavior during shock testing: In 8 cases induced VF was correctly detected and treated; in 4 cases of R-wave-synchronized shock electrical parameters remained stable and normal. Three patients (20%) failed the test. One patient with externalized conductors showed a sudden drop of high-voltage impedance (< 10 Ohm) after a 25 J R-wave-synchronized shock. Two other patients with externalized conductors, undergoing defibrillation testing, showed a short-circuit during shock delivery and the implantable cardioverter defibrillator was unable to interrupt VF.

CONCLUSION

In Riata™ leads the delivery of a low current during routine measurement of high-voltage impedance may not reveal a small short circuit, that can only be evident by attempting to deliver a true shock, either for spontaneous arrhythmias or in the context of a shock testing.

Keywords: Implantable cardioverter defibrillator, Lead failure, Defibrillation testing, Riata™ lead, Externalized conductors

Core tip: The management of Riata™ defibrillator leads is complex and optimal treatment is often carried out on individual basis. These leads are prone to a unique failure mechanism: The conductors can externalize through the silicone insulation (“inside-out” abrasion) and appear outside the lead body leading to electrical failure. The potential role of high-voltage shock testing for these leads has been poorly studied, only sparse reports being available. In Riata™ leads the delivery of a low current during routine measurement of high-voltage impedance may not reveal a small short circuit, that can only be evident by attempting to deliver a true shock, either for spontaneous arrhythmias or in the context of a shock testing. Defibrillation testing (or alternatively synchronized shock) should be considered an important tool to check Riata™ integrity.