Unrecognized Failure of a Narrow Caliber Defibrillation Lead: The Role of Defibrillation Threshold Testing in Identifying an Unprotected Individual

Abstract

In this case report we describe a short circuit in the Riata 1570 defibrillator lead (Riata 1570, St. Jude Medical, St. Paul, MN, USA) that was unsuspected owing to normal lead parameters until defibrillator threshold testing at the time of elective generator change. On this occasion, the short circuit manifested as unsuccessful defibrillation of ventricular fibrillation with immediate battery depletion. This report adds weight to existing concerns over narrow caliber leads, it draws attention to the possibility of lead malfunction despite unremarkable interrogation, and lastly it highlights the potential role of routine defibrillator threshold testing, particularly at elective generator change (an issue that remains sparingly addressed in the existing literature).

Deaths caused by the failure of Riata and Riata ST implantable cardioverter-defibrillator leads

“…That these defects may not be detectable by routine monitoring is underscored by a case report showing that even intraoperative testing may fail to identify a shorted Riata lead. 11 Seven of the 22 Riata and Riata ST lead-related deaths were due to can abrasions that resulted in short circuiting between exposed high-voltage cables and the pulse generator. In these and other high-voltage failures, the pulse generator sustained electrical overstress and was unable to deliver further therapy.…”

Riata silicone defibrillation lead with normal electrical measures at routine ambulatory check: The role of high-voltage shock testing

“…Moreover, in four cases there was no sign of externalization on fluoroscopy[14,16,18]. Our two patients had a 1571-8Fr and a 7000ST-7Fr, both dual-coil, both with EC.…”

“…The potential role of defibrillation testing in the management of Riata™ is currently unclear and has been poorly studied; only sparse reports are available in literature[14-19]. Some authors advocate it at time of pulse generator change[1,4,6,7] but patients at high risk could benefit from the test even before that time.…”

“…Leong et al[14] was the first to describe a case of failure to deliver an appropriate shock by a 8Fr dual-coil 1570 Riata™ (implanted 8 years before) during a DFT performed after generator replacement; lead measurements were normal and stable, in absence of EC. The lead was not extracted but product analysis report of the generator indicated structural damage by a short circuit in the lead, while lead connection with the header box appeared normal.…”

Successful detection of a high-energy electrical short circuit and a “rescue” shock using a novel automatic shocking-vector adjustment algorithm

“…Serious adverse events, including deaths linked to Riata leads, have been reported 3, 4, 5, 6, 7. In these reports, the authors point to the risk of an HV short circuit caused by the inside-out abrasion underneath the shocking coils in the Riata lead family devices, though the incidence rate of internal abrasion short circuits underneath the SVC shock coil is quite low (0.06%) 8 .…”