Implantable cardiac pacemaker

Furthermore, pH determination has been used in other clinical research, both alone and in combination with other measurements. This research includes studies into the relationship between extracellular and intracellular pH in an ischemic heart [6, 7], the pH of airway lining fluid in respiratory disease [8], the study of pH as a marker for pyloric stenosis [9], malnutrition in alkalotic peritoneal dialysis patients [10], pH modulation of heterosexual HIV transmission [11, 12], and wound prevention and treatment [13], In addition, pH changes due to blood acidosis have been used to trigger and pace the ventricular rate of an implanted cardiac pacemaker [14], Research using pH measurements... 

Lithium iodide is the electrolyte in a number of specialist batteries, especially in implanted cardiac pacemakers. In this battery the anode is made of lithium metal. A conducting polymer of iodine and poly-2-vinyl pyridine (P2VP) is employed as cathode because iodine itself is not a good enough electronic conductor (Fig. 2.3a). The cell is fabricated by placing the Li anode in contact with the polyvinyl pyridine-iodine polymer. The lithium, being a reactive metal, immediately combines with the iodine in the polymer to form a thin layer of lithium iodide, Lil, which acts as the electrolyte ... 

Cardiac catheterization, including balloon angioplasty Implanted cardiac pacemakers, implanted defibrillators, and coronary stents... 

Forde, M. and P. Ridgely, 1995, Implantable cardiac pacemakers, in The Biomedical Engineering Handbook, J. Bronzino, ed., CRC Press, Boca Raton, FL, pp. 1258-1269. 

This is one area, like many others in HIT, where the devil is in the detail. For simple and well defined software applications, this argument may be reasonably straight-forward to construct. For example, the software embedded within an implantable cardiac pacemaker is integral to its operation and makes functional a device which has overwhelming and live-saving benefits to patients. Those benefits are straight-forward to derive and, with some analysis, can potentially be quantified. 

Polymer electrolyte batteries have been used in implanted cardiac pacemakers since 1972. The system used is lithium/iodine-polyvinylpyridine. Although the conductivity of the Li ions in Li2l is poor, the current requirements are very small, and the major consideration is the storage of a high energy density of nearly 1 Whcm . ... 

Implantable cardiac pacemakers are electronic devices that treat bradycardia. External pacemakers were developed in the early 1950s. These were large devices that were not portable. Introduction of the transistor in the mid-1950s meant that... 

Lithium-iodine (Li/12) was proposed as a power source for implantable cardiac pacemakers in 1971 [12]. The first pacemaker run by a cell was implanted in 1972 [6]. These cells were originally developed as more reliable and longer lived alternative to the zinc-mercuric oxide cells (see below) used in implantable cardiac pacemakers since they were introduced in 1960 and on into the mid-1970s. However, Li/l2 cells have been the dominant power source for implantable cardiac pacemakers for more than 30 years. 

Lithium-thionyl chloride (Li/SOCl2) cells have seen a number of uses, including remote monitoring (such as residential water meters), various OEM (original equipment manufacturer) electronic devices, military, aerospace, and down-hole oil well monitoring applications. Medical device uses have included implantable heart mmiitors, drug infusion pumps, and some of the earliest implantable cardiac pacemakers [9, 10]. 

Although no longer used, zinc-mercuric oxide (Zn/HgO) cells were the power source of choice for the first commercially viable implantable cardiac pacemakers. More than 3 million Zn/HgO cells were implanted in the 16 years from when the first successful cardiac pacemaker was implanted in 1960 and 1976 [20]. They helped many bradycardia patients until they were eventually supplanted by lithium cells, particularly IAH2, so a brief description of Zn/HgO technology is included here. Zn/HgO cells were also once used in wearable hearing aids. 

Secondary, or rechargeable, cells have been used in medical devices for some time. One of the first batteries to be used for implantable cardiac pacemakers was a custom rechargeable nickel-cadmium battery [6]. Systems to recharge the battery transcuta-neously using inductive methods were developed starting in the late 1950s [42]. 

Greatbatch W, Lee JH, Mathias W, Eldiidge M, Moser JR, Schneider AA (1971) The solid-state lithium battery a new improved chemical power source for implantable cardiac pacemakers. IEEE Trans BioMed Eng BME 18 317-324... 

Parsonnet V, Furman S, Smyth NP, et al. Optimal resources for implantable cardiac pacemakers. Pacemaker Study Group. Circulation 1983 68(1) 226A. 

Furman S. External defibrillation and implanted cardiac pacemakers. Pacing Clin Electrophysiol 1981 4 485-486 (editorial). 

Cooper D, Wilkoff B, Masterson M, Castle M, Belco K, Simmons T, Morant V, Streem S, Maloney J. Effects of extracorporeal shock wave lithotripsy on cardiac pacemakers and its safety in patients with implanted cardiac pacemakers. Pacing Clin Electrophysiol 1988 11 1607-1616. 

On October 8, 1958, in Sweden, forty-three-year-old Arne Larsson became the first person to receive an implanted cardiac pacemaker. He lived to the age of eighty-six. 

Forde M, Ridgely P (2006) Implantable cardiac pacemakers. In Bronzino JD (ed) Medical Devices and Systems, The Biomed Eng handbook, 3rd edn. CRC Press, Taylor and Francis Group, Boca Raton, FL... 

Parsonnet, V. 1972. Power sources for implantable cardiac pacemakers. Chest 61 165-173. 

Most of the implantable cardiac pacemakers need to be replaced because of the battery exhaustion within 5-8 years. The longevity of the IMDs is determined by the battery life. When the service life of the battery ends, it needs to be replaced, causing the patient to undergo painful surgery and incur enormous expenses. In contrast, the main advantage of fuel cells for IMD is its theoretical potential to function as long as the individual is alive. The devices can use substrates that already exist in the body— no artificial fuel and oxidants are required. 

The lithium-iodine combination has been used for most implanted cardiac pacemakers since 1972. It thus has a believable reliability history, at least at human body temperature. Because of its critical main use, the lithium-iodine cell comes in a hermetically sealed (laser-welded) nickel or steel container, which makes it more expensive than other types ( 5-8 for the 200-350mAh coin-shaped cells). Yet the high quality of the chemical processing and encapsulation makes it a good choice where very long shelf life (10 years and beyond) is the objective. 

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