The reliability of the power sources used in implantable cardiac defib
rillators is critical due to the life-saving nature of the device. Ach
ieving a high reliability power source depends on several systems func
tioning together. Appropriate cell design is the first step in assurin
g a reliable product. Qualification of critical components and of the
cells using those components is done prior to their designation as imp
lantable grade. Product consistency is assured by control of manufactu
ring practices and verified by sampling plans using both accelerated a
nd real-time testing. Results to date show that lithium/silver vanadiu
m oxide cells used for implantable cardiac defibrillators have a calcu
lated maximum random failure rate of 0.005% per test month.