Guidant's Cardiac Rhythm Management Quality System has determined that the
atrial therapy (AVT) subgroups of certain Guidant ICD and CRT-D product
families are subject to a condition in which a random memory error causes
functional latching that limits available therapy. Engineering analysis has
determined that latching can only occur when storing tachy detection/therapy
episode information to affected memory. Two occurrences have been confirmed
out of approximately 20, 950 devices implanted to date; none have resulted in
patient injury beyond device replacement.
Latching of AVT devices will suspend detection and treatment of atrial and
ventricular arrhythmias. Telemetry and programming are not available.
In a latched state, battery usage may increase, but battery status indicators will
not be available. In the event that latching occurs during delivery of ATP
therapy, ATP therapy delivery could continue independent of patient need.
Device replacement is required if latching occurs.
Currently, programming options are available to further diminish the already
very low probability of even one more latching event.
Programming options |
Probability of latching |
Probability of latching with
continuous ATP therapy |
A) No programming mitigation |
0.005% (1 per 20,000 devices)
|
0.000265%
(1 per 377,000 devices)
|
B) Program Atrial Tachy
Episode - Data Storage to 0%
|
0.000066%
(1 per 1,520,000 devices)
|
0.00000352%)
(1 per 28,400,000 devices)
|
C) Program Atrial Tachy
Episode
Data Storage to 0% and
program all ATP therapies to
OFF |
0.000066%
(1 per 1,520,000 devices) |
Zero. Although functional latching may still occur, it will not result in continuous ATP therapy. |
Following implantation of a
software solution (year-end)
|
Zero
Return to normal
programming
|
Zero
Return to normal
programming
|
Only atrial therapy AVT subgroups of Guidant ICD and CRT-D product families
are impacted by this anomaly. This issue does not impact standard ICDs and
CRT-Ds.
Devices Impacted:
Device family
|
Model Numbers
|
Population
|
Confirmed Events
|
VENTAK PRIZM AVT
|
1900 |
714 |
0 |
VITALITY AVT
|
A135, A155 |
19,446 |
2 |
CONTAK RENEWAL 3 AVT*
|
M150, M155 |
125 |
0 |
CONTAK RENEWAL 3 AVT HE *
|
M157, M159 |
37 |
0 |
CONTAK RENEWAL 4 AVT*
|
M170, M175 |
255 |
0 |
CONTAK RENEWAL 4 AVT HE*
|
M177, M179 |
369 |
0 |
Guidant is currently developing a non-invasive software solution for VITALITY
AVT and all RENEWAL AVT devices. This solution is expected by year-end,
pending regulatory approval.
While programming options discussed above will significantly reduce the risks of
functional latching in a PRIZM AVTs, estimates of normal services life for
remaining PRIZM AVTs indicate that few will be in service by the time a
software solution can be developed and approved. Accordingly, no software
update will be developed for PRIZM AVT.
