Medical pacemakers (Identity SR model 5172, Identity DR model 5370 and Identity XL DR model 5376) - perform a manual measured data reading in follow-ups

(St Jude Medical UK Ltd) a programmer software anomaly can occur when these devices are used together, which can cause inaccurate display of battery voltage, battery longevity and elective replacement indicator (ERI) status. (MDA/2006/065)

23 November 2006 at 14:00


Action deadlines for the Safety Alert Broadcast System (SABS)

Deadline (action underway): 04 January 2007, Deadline (action complete): 27 February 2007


St Jude Medical pacemakers: Identity SR model 5172, Identity DR model 5370 and Identity XL DR model 5376.

St Jude Medical programmers: APS III model 3500, APS III model 3510 and Merlin PCS model 3650.

Pacemakers: Programmers:
Identity SR model 5172, Identity DR model 5370, Identity XL DR model 5376 APS III model 3500/3510 installed with software version 6.1.1 and earlier, Merlin PCS model 3650 installed with software version 4.1.1 and earlier


Potential for inaccurate display of:

  • battery voltage
  • expected battery longevity
  • Elective Replacement Indicator (ERI) status

at initial programmer interrogation.

St Jude Medical has advised MHRA that a programmer software anomaly can occur when the above programmers and pacemakers are used together. The manufacturer notified their UK customers of this issue in a letter dated 12 October 2006 (see appendix).

The problem, which has only affected 53 out of approximately 199,100 pacemakers, results in the display of inaccurate battery voltage, expected battery longevity, and ERI status. The anomaly does not affect the pacemaker’s actual battery voltage, longevity or functionality. Display of inaccurate data only occurs at initial programmer interrogation. Correct battery voltage measurements and longevity status etc. will only be displayed when a manual measured data reading is performed.

The anomaly is the result of a software interaction where a memory location within the pacemaker changes state. When this occurs, the data read on initial interrogation (from the pacemaker’s memory) is not up to date. This affects the calculations for battery voltage, remaining longevity, ERI status and magnet rate and therefore the displayed information is incorrect. In addition, as pacemakers approach the elective replacement time, this could result in the reporting of inappropriately high battery voltage and remaining longevity and could result in a delay in indicating ERI status.

To correct this problem, St Jude Medical has developed a software upgrade which, when installed on the programmer, will automatically correct an affected pacemaker memory location and ensure accurate battery status information is displayed. St Jude Medical advises that this will take place on first pacemaker interrogation following programmer software upgrade and will not extend the time needed for the appointment. St Jude Medical plans to release the upgraded software in December 2006 and anticipates that all potentially affected programmers in the UK will receive the software upgrade by the end of January 2007.

St Jude Medical has already communicated this information to all UK hospitals that have received potentially affected pacemakers and programmers. Neither St Jude Medical nor MHRA have received any reports of adverse clinical events associated with this issue.


  • During programmer follow-up of the above pacemakers, ensure that a manual measured data reading is performed to display true battery voltage and longevity status.
    • For patients with pacemakers within two years of the longevity published in the pacemaker manual, perform a patient follow-up as soon as practically possible, giving priority to pacing dependent patients.
    • For patients with pacemakers not within two years of published longevity, perform follow-up at the scheduled intervals.
    • If you already routinely perform a manual measured data reading during follow-up, there is no need for any action.
  • Do not use magnet application alone to assess ERI or End Of Life (EOL) status, until programmer software has been upgraded.
  • Usual patient follow-up may be resumed on completion of programmer software upgrade by St Jude Medical.
  • Report any subsequent programmer/pacemaker problems to St Jude Medical and MHRA.

Action by

All cardiologists, cardiothoracic surgeons and cardiac physiologists who manage patients implanted with these devices.


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:

SABS liaison officers for onward distribution to all relevant staff including:

  • Cardiac pacemaker physiologists
  • Cardiologists with pacemaker responsibilities
  • Cardiothoracic surgeons
  • Clinical governance leads
  • Medical directors
  • Nursing executive directors
  • Risk managers

Healthcare Commission (CHAI) to:Headquarters for onward distribution to:

  • Hospitals in the independent sector


Enquiries to the manufacturer should be addressed to:

Dr Jennifer Cooke
Regulatory Manager
St Jude Medical UK Ltd
Capulet House
Stratford Business & Technology Park
Banbury Road
Stratford-upon-Avon CV37 7GX

Tel: 01789 207 600
Fax: 01789 207 601


Enquiries to the MHRA should quote reference number 2006/010/010/081/014 and be addressed to:

Technical aspects

Miss Celina Cundy or Mr Peter Solesbury
Medicines & Healthcare products Regulatory Agency
Market Towers
1 Nine Elms Lane
London SW8 5NQ

Tel: 020 7084 3305/3215
Fax: 020 7084 3106

E-mail: &

Clinical aspects

Dr Susanne Ludgate
Medicines & Healthcare products Regulatory Agency
Market Towers
1 Nine Elms Lane
London SW8 5NQ

Tel: 020 7084 3123
Fax: 020 7084 3111


Change of address or removal from address list for Healthcare Commission:

Healthcare Commission
Finsbury Tower
103-105 Bunhill Row

Tel: 020 7448 0842


How to report adverse incidents

Incidents relating to medical devices must be reported to the Medicines and Healthcare products Regulatory Agency (MHRA) as soon as possible.

Further information about reporting incidents; online incident reporting facilities; and downloadable report forms are available from MHRA’s website (

Alternatively, further information and printed incident report forms are available from:

MHRA Adverse Incident Centre
Medicines and Healthcare products Regulatory Agency
Market Towers, 1 Nine Elms Lane
London SW8 5NQ

Telephone 020 7084 3080 or Fax 020 7084 3109 or e-mail: answerphone service operates outside normal officer hours)

Medical Device Alerts are available in full text on the MHRA website:

Further information about SABS can be found at

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