Teligen and Cognis defibrillators - risks for devices implanted subpectorally

(Boston Scientific) specific models of defibrillators implanted subpectorally have a risk of loss of shock therapy, inappropriate shock therapy, loss of pacing therapy or loss of anti-tachycardia pacing. (MDA/2010/012)


Teligen implantable cardioverter defibrillators (ICDs) and Cognis cardiac resynchronisation therapy defibrillators (CRT-Ds) – specific models.
Manufactured by Boston Scientific.

Teligen implantable cardioverter defibrillator and Cognis cardiac resynchronisation therapy defebrillator manufactured by Boston Scientific

Models affected by this alert:

  • Teligen ICDs model numbers E102, E110, E111, F102, F110 and F111.
  • Cognis CRT-Ds model numbers N106, N107, N108, N118, N119, P106, P107 and P108.


For devices implanted subpectorally there are risks of:

  • loss of shock therapy
  • inappropriate shock therapy
  • loss of pacing therapy
  • loss of anti-tachycardia pacing

The manufacturer has established that the bond between the header and case of these specific models can be weakened either from significant forces associated with a subpectoral implant procedure or when a device in a subpectoral position is repeatedly pushed against a rib during contraction of the pectoralis muscle.

The following factors may have an impact on the risk of failure if affected devices are implanted subpectorally:

  • exact location of the patient’s ribs relative to the device
  • body size and/or muscle mass of the patient (risk increases for larger or muscular patients)
  • activity level and/or occupation of the patient (risk increases for more active patients)
  • increased implantation duration.

The manufacturer issued a Field Safety Notice in December 2009 informing clinicians about this issue.

Extent of the problem

The manufacturer has confirmed that approximately 2,500 affected Teligen and Cognis devices have been distributed on the UK market since these models were released in June 2008. They have estimated that approximately 5% of affected devices are implanted subpectorally worldwide. Devices implanted subcutaneously are not included in this advisory.

To date the manufacturer has confirmed two (non-UK) reports of device malfunction associated with this issue out of approximately 77,000 devices sold worldwide. Both devices required early replacement (at four and five months post-implant) as they had delivered inappropriate shocks. The manufacturer has not identified a mean time-to-failure for this problem.

Identifying failed devices

There are no specific tests to identify a weakened header bond.

Standard in-clinic monitoring and troubleshooting steps for lead-related issues (including isometrics and manipulating the pocket while watching for noise on electrograms and/or inappropriate pacing or shock therapy) are recommended but cannot definitely distinguish a loose header from a failed lead or bad connection of the lead.

Evidence of a weakened header bond is not typically visible via X-ray or fluoroscopy. Should this weakening progress to wire fracture and complete separation of the header from the titanium case it may be visible on X-ray or fluoroscopy.

Early stages of a weakened header bond may only cause subtle lead impedance changes (in the tens or hundreds of ohms), whereas in the later stages there may be a very large change in lead impedance.

If available, the LATITUDE patient management system may also be helpful for monitoring patients.

Availability of modified devices

The manufacturer has made manufacturing process changes to strengthen the bond between the header and case. Modified devices are expected to be available in the UK from February 2010.


  • Review records to identify patients with an affected device implanted subpectorally.
  • Recall affected patients for baseline measurements within six weeks, giving priority to those who are pacing-dependent or who have not been followed up within the previous three months.
  • Consider programming ‘Daily Measurement Alerts’ for lead impedance to ‘On’.
  • Consider prophylactic replacement of affected devices in high risk patients.
  • Remind affected patients to contact their clinic if they receive shocks.
  • Follow up affected patients at three-month intervals (as stated in the manufacturer’s instructions for use).
  • Avoid subpectoral implantation of these models.
  • Report device failures and adverse incidents to Boston Scientific and the MHRA.


This MDA has been distributed to:

  • NHS trusts in England (Chief Executives)
  • Care Quality Commission (CQC) (Headquarters)
  • NHS boards in Scotland (Chief Executives)
  • NHS boards and trusts in Wales (Chief Executives)
  • Primary care trusts in England (Chief Executives)

Onward distribution

Please bring this notice to the attention of all who need to know or be aware of it. This may include distribution by:

Trusts to:
CAS and SABS (NI) liaison officers for onward distribution to all relevant staff including:

  • A&E consultants
  • A&E departments
  • A&E directors
  • A&E nurses
  • Cardiac laboratory technicians
  • Cardiologists
  • Cardiology departments
  • Cardiology nurses
  • Cardiology, directors of
  • Cardiothoracic surgery directors
  • Clinical governance leads
  • Risk managers

Care Quality Commission (CQC) (England only) to:
The MHRA considers this information to be important to:

  • Care homes providing nursing care (adults)
  • Care homes providing personal care (adults)
  • Clinics
  • Hospitals in the independent sector
  • Independent treatment centres
  • Private medical practitioners

Primary care trusts to:
CAS liaison officers for onward distribution to all relevant staff including:

  • General practitioners

Manufacturer contact

Cait Cowley
Boston Scientific
Breakspear Park
Breakspear Way
Hemel Hempstead
Herts HP2 4TZ

Tel: 01442 411 673
Fax: 01442 411 816



If you have any comments or feedback on this Medical Device Alert, please email us at


If you are in England, please send enquiries about this notice to the MHRA, quoting reference number 2009/011/030/081/012.

Technical aspects

Juliet Aharoni or Hazel Randall
Medicines and Healthcare products Regulatory Agency
Market Towers
1 Nine Elms Lane

Tel: 020 7084 3177/3287
Fax: 020 7084 3106

Email: or

Clinical aspects

Christopher Brittain
Medicines and Healthcare products Regulatory Agency
Market Towers
1 Nine Elms Lane

Tel: 020 7084 3126
Fax: 020 7084 3111


How to report adverse incidents
Please report via our website: Reporting adverse incidents involving medical devices.
Further information about CAS can be found on the Central Alerting System website .

Northern Ireland

Alerts in Northern Ireland will continue to be distributed via the NI SABS system.

Enquiries and adverse incident reports in Northern Ireland should be addressed to:

Northern Ireland Adverse Incident Centre (NIAIC)
Health Estates
Estate Policy Directorate
Stoney Road
BT16 1US

Tel: 02890 523 704
Fax: 02890 523 900


Northern Ireland Adverse Incident Centre (NIAIC)

How to report adverse incidents in Northern Ireland

Please report directly to NIAIC, further information can be found on the NIAIC website .

Further information about SABS can be found on the SABS website .


Enquiries and adverse incident reports in Scotland should be addressed to:

Incident Reporting and Investigation Centre
Health Facilities Scotland
NHS National Services Scotland
Gyle Square
1 South Gyle Crescent
EH12 9EB

Tel: 0131 275 7575
Fax: 0131 314 0722


Health Facilities Scotland - Incident Reporting and Investigation Centre .


Enquiries in Wales should be addressed to:

Dr Sara Hayes
Senior Medical Officer
Medical Device Alerts
Welsh Assembly Government
Cathays Park
CF10 3NQ

Tel: 029 2082 3922


Download documents

Medical Device Alert: Teligen and Cognis defibrillators - specific models, manufactured by Boston Scientific (MDA/2010/012) (203Kb)

Published 17 December 2014