- Email: [email protected]
To the Editor—Response
Letters to the Editor 2.
e7 Minneapolis Heart Institute Minneapolis, Minnesota
Swerdlow CD, Gunderson BD, Ousdigian KT, et al. Downloadable algorithm to reduce inappropriate shocks caused by fractures of implantable cardioverterdefibrillator leads. Circulation 2008;118:2122–2129.
To the Editor—Response:
Reference 1.
The Medtronic Lead Integrity Alert (LIA) is a potentially valuable method for detecting Sprint Fidelis pace-sense conductor fractures before they cause adverse clinical events, such as inappropriate shocks or asystole due to pacing inhibition. The LIA combines lead noise detection with enhanced impedance monitoring, and our preliminary clinical experience suggests that this approach is superior to impedance monitoring alone. The LIA is implemented by a RAMware download to most Medtronic ICD pulse generators. One risk of a software change is an unintended modification to a device’s settings or features. As described by Arias et al, the LIA apparently turns off an enabled safety feature that alerts patients if their ICD arrhythmia detection has been deactivated. The “VF Detection OFF, 3⫹VF or 3⫹FVT Rx OFF” alert is nominally on and emits a high tone when triggered. This safety feature is particularly important because deaths have occurred as the result of accidental or inadvertent ICD deactivation, including failure to reactivate devices after surgical procedures.1 At present, we do not know if the EnTrust ICDs are the only Medtronic models affected and whether simply programming the alert back on is a permanent solution. However, this experience underscores the importance of conducting careful clinical studies to validate software changes to implanted devices before they are released for general use. Robert G. Hauser, MD, FACC, FHRS [email protected]
Hauser RG, Kallinen L. Deaths associated with implantable cardioverter defibrillator failure and deactivation reported in the United States Food and Drug Administration Manufacturer and User Facility Device Experience Database. Heart Rhythm 2004;1:399 – 405.
To the Editor—Response: As Dr. Arias correctly noted, the Medtronic Lead Integrity Alert (LIA) significantly increases the likelihood of detecting a potential defibrillation lead fracture that could result in inappropriate therapy. The company recently learned of an interaction between LIA and the company’s EnTrust implantable cardioverter-defibrillators (ICDs), where installing or removing the LIA on these devices inadvertently turns off two audible patient alerts, which are among several features designed to help identify disabled detection. Device therapy is not affected, and Medtronic is not aware of any patient injuries related to these alerts being turned off. Medtronic began informing physicians of this interaction in November 2008. The company recommends that physicians continue to install LIA on EnTrust devices using the Medtronic 2090 Programmer and then program these alerts ON, if desired. Warren Watson [email protected] VP Cardiac Rhythm Disease Management VP Implantable Product Development Medtronic, Inc. Minneapolis, Minnesota
e7 Minneapolis Heart Institute Minneapolis, Minnesota
Swerdlow CD, Gunderson BD, Ousdigian KT, et al. Downloadable algorithm to reduce inappropriate shocks caused by fractures of implantable cardioverterdefibrillator leads. Circulation 2008;118:2122–2129.
To the Editor—Response:
Reference 1.
The Medtronic Lead Integrity Alert (LIA) is a potentially valuable method for detecting Sprint Fidelis pace-sense conductor fractures before they cause adverse clinical events, such as inappropriate shocks or asystole due to pacing inhibition. The LIA combines lead noise detection with enhanced impedance monitoring, and our preliminary clinical experience suggests that this approach is superior to impedance monitoring alone. The LIA is implemented by a RAMware download to most Medtronic ICD pulse generators. One risk of a software change is an unintended modification to a device’s settings or features. As described by Arias et al, the LIA apparently turns off an enabled safety feature that alerts patients if their ICD arrhythmia detection has been deactivated. The “VF Detection OFF, 3⫹VF or 3⫹FVT Rx OFF” alert is nominally on and emits a high tone when triggered. This safety feature is particularly important because deaths have occurred as the result of accidental or inadvertent ICD deactivation, including failure to reactivate devices after surgical procedures.1 At present, we do not know if the EnTrust ICDs are the only Medtronic models affected and whether simply programming the alert back on is a permanent solution. However, this experience underscores the importance of conducting careful clinical studies to validate software changes to implanted devices before they are released for general use. Robert G. Hauser, MD, FACC, FHRS [email protected]
Hauser RG, Kallinen L. Deaths associated with implantable cardioverter defibrillator failure and deactivation reported in the United States Food and Drug Administration Manufacturer and User Facility Device Experience Database. Heart Rhythm 2004;1:399 – 405.
To the Editor—Response: As Dr. Arias correctly noted, the Medtronic Lead Integrity Alert (LIA) significantly increases the likelihood of detecting a potential defibrillation lead fracture that could result in inappropriate therapy. The company recently learned of an interaction between LIA and the company’s EnTrust implantable cardioverter-defibrillators (ICDs), where installing or removing the LIA on these devices inadvertently turns off two audible patient alerts, which are among several features designed to help identify disabled detection. Device therapy is not affected, and Medtronic is not aware of any patient injuries related to these alerts being turned off. Medtronic began informing physicians of this interaction in November 2008. The company recommends that physicians continue to install LIA on EnTrust devices using the Medtronic 2090 Programmer and then program these alerts ON, if desired. Warren Watson [email protected] VP Cardiac Rhythm Disease Management VP Implantable Product Development Medtronic, Inc. Minneapolis, Minnesota