Implantable cardioverter defibrillators (ICDs) - ensure you have updated software for models 3510 and 3510+ ICD programmers

(St Jude Medical) potential reduction in number of shocks (skipped charge) delivered per therapy episode and inappropriate rate responsive pacing for up to 90 minutes. (MDA/2005/045)

Deadline (Action underway): 19 August 2005 - Action plan to be agreed and actions started. Deadline (Action complete): 13 January 2006 - All actions to be completed.


St Jude Medical implantable cardioverter defibrillators (ICDs):

Atlas DR model: V-242    
Atlas Plus DR/VR/HF models: V-243, V-193, V-193C, V-340, V-341, V-343    
Epic DR/HF models: V-233, V-337, V-338    
Epic Plus DR/VR/HF models: V-236, V-239, V-196, V-239T, V-196T, V-350    


St Jude Medical has informed the MHRA and all customers (Dear Doctor Letter dated 14 June 2005) that the above Atlas and Epic ICD models have the potential to experience either or both of the following problems:

‘Skipped charge’

This problem is due to a software anomaly, which may occur as the battery approaches elective replacement indication (ERI). A prematurely terminated capacitor charging cycle (‘skipped charge’) can result in a reduction in the number of shocks delivered per therapy episode; in a worst case scenario three shocks may be delivered instead of six. The problem may occur on alternate capacitor charge cycles, but the first shock will always be delivered. The programmed energy per shock is not affected by this problem.

The anomaly affects all Atlas and Epic ICD models listed above having a serial number below 225000. There are 844 affected devices in the UK, all of which were distributed since January 2004. The anomaly can be corrected by a software upgrade (see below). Therefore St Jude Medical has not recalled unimplanted ICDs affected by this anomaly as they will be automatically updated during programmer use at implantation.

No risk to patients implanted with affected devices is expected providing the downloading of the software upgrade to these devices is arranged well before their battery reaches ERI.

Inappropriate rate responsive pacing

Inappropriate higher rate pacing may be initiated without being indicated by physiological need, when rate responsive pacing is programmed ‘on’ during automatic and clinician initiated capacitor reformation. The problem does not occur during capacitor charging prior to therapy delivery since automatic rate response function is suspended during arrhythmia detection.

This anomaly is due to an out of specification component (hybrid circuit) and it is caused by electrical ‘noise’ being misinterpreted as a physiologically derived signal, during capacitor reformation. This misinterpretation can cause the pacing rate to increase up to the maximum programmed sensor rate for up to 90 minutes.

The anomaly can occur in all Atlas and Epic ICD models listed above with serial numbers below 141000. This affects 609 implanted devices in the UK; St Jude Medical has informed the MHRA that they have recalled and retrieved all UK unimplanted ICDs affected by this anomaly.

For implanted devices, a software upgrade (see below) will manage this anomaly in patients by suspending rate responsive pacing during capacitor charging and for up to 90 minutes afterwards. If rate responsive pacing is already in progress when capacitor charging takes place, the rate response function will be suspended and the pacing rate will gradually reduce to the programmed base rate for a period of up to 90 minutes.

Software updated

St Jude Medical has released software version 4.8.5 for its 3510 and 3510+ programmers to manage both anomalies and plans to upgrade all programmers in the UK by 27 July 2005. When performing ICD interrogation for the first time with an upgraded programmer, automatic downloading of the software upgrade from the programmer t the ICD will take approximately 45 seconds.

No adverse events regarding these anomalies have been reported to St Jude Medical or the MHRA.


  • Verify that all St Jude Medical Model 3510 and 3510+ ICD programmers have been upgraded by St Jude Medical with software version 4.8.5 (or higher) by 27 July 2005.
  • Identify all patients implanted with the affected Epic or Atlas ICDs (serial number below 225000).
  • Ensure that identified patients are followed up (including interrogation of ICDs using a St Jude Medical upgraded programmer Model 3510 or 3510+):* by the end of September 2005, where the affected implanted devices are programmed at higher electrical current settings
  • by the end of December 2005, for all other affected implanted devices.

  • Report any instances of device failure to MHRA and St Jude Medical.
  • Report any explants to the National Pacing and ICD database.


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


  • Liaison officers (for onward distribution)
  • Accident & emergency departments
  • Cardiac pacemaker/ICD technicians
  • Cardiologists
  • Clinical governance leads
  • Medical directors
  • Nursing executive directors
  • Risk managers


  • Headquarters (for onward distribution)
  • Hospitals in the independent sector


  • Liaison officers (for onward distribution)
  • Clinical governance leads
  • Directors of public health


Enquiries to the manufacturer/National Pacing and ICD Database should be addressed to:

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

Tel: 01789 207 600Fax: 01789 207 601


National Pacing and ICD Database
PO Box 9205
Bridge of Weir
PA11 3DZ

Tel: 01505 612 829Fax: 01505 612 829


Enquiries to the MHRA should quote reference number 2005/006/020/291/010 and be addressed to:

Technical aspects:

Dr Crina Cacou or Mr Peter M Solesbury
Medicines & Healthcare products Regulatory Agency
Market Towers
1 Nine Elms Lane
London SW8 5NQ

Tel: 020 7084 3338/3215Fax: 020 7084 3106

Dr Jon Hopper
Medicines & Healthcare products Regulatory Agency
Market Towers1 Nine Elms Lane
London SW8 5NQ

Tel: 020 7084 3126Fax: 020 7084 3111

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

Healthcare Commission
Finsbury Tower
103-105 Bunhill Row
London EC1Y 8TG

Tel: 020 7448 0842


Document download

MDA/2005/045 - St Jude Medical implantable cardioverter defibrillators (ICDs).

Published 17 December 2014