Medical device manufacturer, Sorin, has issued a field safety notice concerning ISOLINE defibrillation leads (Model numbers: 2CR5, 2CR6 and 2CT6).

As of 31 December 2012, Sorin has confirmed 30 cases out of 13500 units implanted worldwide (0.222%) where the analysis of the returned leads identified internal insulation breach under the right ventricular (RV) and/or Superior Vena Cava (SVC) defibrillation coil electrode. In each of the 30 identified cases, the internal insulation breach of the silicone lumen was observed under the RV and/or SVC defibrillation coil, i.e. where the microcables are not coated with ETFE, resulting in a contact between the conductors, thus leading to low pacing impedance and/or ventricular oversensing, and/or inappropriate therapy. It should be noted that in case of ventricular oversensing, pacing is inhibited. No early indicator that could have warned of a potential issue has been identified in those cases.

In depth investigation by the manufacturer determined that the insulation abrasion by the microcable of the ISOLINE lead models under the RV or SVC defibrillation electrode may be attributed to particular and rare implant conditions that induce bending, compression and/or torsion on the lead, thus promoting internal abrasion of the silicone lumen by pushing the microcable against the lumen wall.

According to the manufacturer, no permanent serious injury or death has been reported as a result of the confirmed malfunction.

The manufacturer provides the following recommendations:

• Leads which are not implanted yet, shall not be used and should be returned to Sorin CRM.
• Considering the low occurrence rate of the issue, prophylactic replacement or removal of any ISOLINE lead is not recommended in patients whose ISOLINE lead has not shown any electrical malfunction.
• Physicians should continue to regularly monitor their patients implanted with ISOLINE leads. During follow up, standard checks should be conducted as recommended in the HRS/EHRA expert consensus on the monitoring of Cardiovascular Implantable Electronic Devices: battery voltage, pacing & sensing operation, lead impedances, arrhythmias detected by the device, etc. Recorded treated and non-treated episodes should be carefully reviewed.
• In the absence of any evidence of malfunction, standard follow up intervals apply (3 months intervals, as recommended in the Sorin ICD labeling); reprogramming of VT/VF detection parameters could be evaluated (such as extending the persistence); however, this should be weighed against delaying appropriate therapy. At the next routine follow up, patients should be informed to contact physicians should they experience shock therapy.
• In case of evidence of a lead issue, physicians should consider replacing the lead, while weighing the risks and benefits of extracting the lead compared to capping it and leaving it in place. The decision to remove a lead should be taken on an individual basis, as described in HRS guidelines. Any event associated to a potentially defective ISOLINE lead should be reported to Sorin CRM; any extracted lead should be returned to Sorin CRM for analysis.
• When the ISOLINE lead is connected to a remote monitoring enabled ICD or CRT-D device, appropriate alert parameter(s) programming shall be considered. For Paradym RF family, physicians should consider programming the following alerts:
  • RF communication to "ON"
  • Alerts to "ON"

According to the local supplier, Innotronik Hong Kong Limited, the affected devices were distributed in Hong Kong.

If you are in possession of the products, please contact your supplier for necessary actions.

Posted on 29 January 2013