Implantable cardiac defibrillator batteries

Silver, copper and other oxosalts have been extensively studied as cathodes in laboratory cells commercial power sources, principally for pacemakers, using silver chromate were manufactured until the 1980s, and silver vanadate or silver vanadium oxide (Ag2V4On), first reported by workers at Wilson Greatbatch Ltd, is currently used as cathode in implantable cardiac defibrillator batteries. 

Takeuchi, E.S. 1995. Reliability systems for implantable cardiac defibrillator batteries. J. Power. Sources. 54 115-119. 

Leifer et al. [105]. used Li MAS NMR to study the strucmre of lithiated silver vanadium oxide, Liy4g2V40n, where x = 0.72,2.13, and 5.59. This compound is used in biomedical applications as a primary battery, particularly as the power source for implantable cardiac defibrillators (ICDs). Silver vanadium oxide is a vanadium bronze with semiconducting properties. It has been used successfully as a cathode material in the battery of ICDs due to its high rate capability and its high theoretical capacity (315 mAh/g) to 2 V. Electrochemical and structural studies of the average structure were performed by various authors who concluded that the systems undergoes a multistep reduction mechanism and forms silver metal in the early stage of the overall reaction [106-108]. 

In this entry are discussed a few of the specialized batteries for medical devices that are portable or wearable (carried with the patient, like hearing aids), or implantable (surgically placed inside the body as with neurostimulation pain management devices). There is a focus on the batteries designed for a few of the more common applications - implantable cardiac rhythm management (cardiac pacemakers and defibrillators), pain management, and hearing loss devices. 

High-rate designs are employed in cardiac defibrillators, while moderate rate units find applications in implantable neurosimulators and drug infusion devices. Lithium/SVO batteries are employed for biomedical applications and as such must be produced under the Good Manufacturing Practices (GMP) for medical devices of the U.S. Food and Drug Administration. 

Medical Device Batteries describes wearable and implantable medical devices powered by batteries. Devices include those that are used for cardiac rhythm management (pacemakers, defibrillators, and heart failure devices), hearing loss, bone growth and fusirm, drug delivery for therapy or pain relief, nerve stimulation for pain management, urinary incompetence and nervous system disorders, vision, diagnostic measurements and monitoring, and mechanical heart pumps. 

Takeuchi ES, Leising RA, Spillman DM, Rubino R, Gan H, Takeuchi KJ, Marschilok AC (2004) Lithium batteries for medical applications, hi Nazii G-A, Pistoia G (eds) Lithium batteries science and technology. BQuwer, Boston, pp 686-700 Untereker DF, Crespi AM, Rorvick A, Schmidt CL, Skarstad PM (2007) Power systems for implantable pacemakers, cardioverters, and defibrillators. In Ellenbogtai KA, Kay GN, Lau C-P, Wilkoff BL (eds) Clinical cardiac pacing and defibrillation, 3rd edn. Saunders, Philadelphia, pp 235-259... 

Epstein AE, Plumb VJ, Kitkk KA, and Kay GN. Pacing threshold increase in non-thoractomy implantable defibrillator leads implications for battery longevity and margin of safety. J Int Cardiac Electrophysiol 1997 1 131-134. 

According to heart specialists, four distinct types of medical devices can be used to treat cardiac diseases, namely pacemakers, cardioverters, defibrillators, and left-ventricular assist devices. In addition, the total artificial or mechanical heart needs to be powered by batteries with an emphasis on reliability, safety, and OCV with no electrical surges and voltage fluctuations. Generally, cardiac pacemakers are prescribed by heart specialists when the cardiac rhythm is too slow or when the patient has an abnormal heart beat. This device is implanted in the patient s chest. The implanted pacemaker detects the slow heart rate and sends electrical impulses to stimulate the heart muscle. An electrical signal from the muscle is fed back to the device to make appropriate corrections in the stimulation parameters, which will normalize the heart rate within a hundred microseconds or so. 

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