Power Sources

The CIED needs to be replaced because of battery exhaustion. The device will keep its normal operation for 3-6 months since the time when Elective Replacement Indication is reached, then it will keep on working in a simplified mode until the end of battery life. Thus, there is plenty of time to plan replacement within 3 months from ERI. Usually this occurs in a day-hospital regimen, unless system upgrade with lead/s addition is anticipated. As CIEDs are hermetically sealed, battery and circuitry are a single device: replacement means that a new CIED is placed in the pocket

The Power source of CIEDs has to address very different tasks:

  • Deliver low-voltage stimulation daily for many years (pacemakers and CRT-Pacemakers)
  • Deliver high-voltage therapy on rare occasion (ICDs)
  • Deliver both low-voltage and high-voltage therapy (CRT defibrillators)
  • Provide customary activity (current drain for the “housekeeping” function , rhythm monitoring and data storage).

Over years the chemistry of batteries, of capacitors, and the packaging of devices has improved so much that CIED downsizing has been possible at no compromise with longevity.
Beyond battery technology, the use of algorithms for automatic verification of stimulation and output adjustment allows to minimize the battery current drain while preserving longevity.
Indeed, dual chamber pacemakers manufactured since 1998 have provided a > 10 years service of life at 100% ventricular pacing thanks to such an algorithm. (see also Follow up)

Why is CIED longevity important ?

Several reasons highlight its importance:
CIED infection is 4-fold higher at replacement compared to implantation
CIED infection has substantial mortality risk despite best medical treatment
ICD (shorter longevity) infection is more common than pacemaker infection
Repeated surgery is unpleasant for everyone
Replacement is only needed to provide a new power source, as software in the CIED microprocessor can be upgraded by telemetry non invasively
Rechargeable batteries are feasible, but manufacturers are deterred by health systems, who never planned to cover reimbursement for battery recharging or software update
90% of Patients have reported to prefer a longer lasting, though bigger, CIED compared to a smaller but less lasting one
The cost of therapy is markedly decreased by a superior longevity

Indeed, in any chronic disease the cost of therapy should be calculated on the long term, not based on the up-front cost. When this concept is applied to the “presumed” expensive CIEDs, one discovers that CIED therapy is indeed comparable to many other treatments, for instance medications for Hypertension, where a 12 and 8 years longevity is expected respectively for pacemakers and ICDs.
Indeed, daily costs would be:
1.2 – 3.6 € for hypertension treated by 2 to 3 drugs
0.6 € for AVB treated by a dual chamber pacemaker,
2.2 € for primary/secondary prevention single chamber ICD,
4.7€ for a CRT-Defibrillator, respectively.