Nordic Life Science 1
n addition to longevity, lithium-ion batteries ha
ve another advantage in pacemakers. When the battery is getting closer to the end of its life, the voltage begins to decrease, and due to the decreasing voltage electrical designers can design an end of life indicator for the pacemaker that allows the device to inform the doctor that a new battery is needed. It can then be changed safely before it discharges completely. Lithium-ion batteries can also be used for other medical applications, such as neuro-stimulation and in insulin pumps for diabetics. The pacemaker has paved the way for the development of implantable defibrillators, diabetes insulin pumps, hip replacements and artificial limbs. During the first decades after the pacemaker was invented, it could only emit one steady pulse. Several refinements have been made since then, for example the titanium casing (replacing the epoxy resin and silicone rubber), non-invasively programmable pacemakers, dual-chamber pacemakers, steroideluting leads, rate-responsive pacemakers, microprocessordriven pacemakers, and bi-ventricular pacing for heart failure (Aquilina, Images Paediatr Cardiol, 2006). Today the pacemaker can adjust itself to the patient’s individual heart rhythm, at any level of physical activity. It can also synchronize the right and the left chambers during congestive heart failure and via a computer it can communicate wirelessly with healthcare professionals 24 hours a day. Today’s pacemakers are as small as a coin and weigh only 13 to 40 grams. They are operated under the skin at the collarbone and the stimulating electrode is inserted into the heart through a vein. The operation is performed through local anesthesia and takes less than one hour. In a typically modern pacemaker the battery’s capacity is similar to a cell phone’s battery, but it can last up to ten years. In recent year there have also been several improvements when it comes to pacemaker technologies. Dave Fornell at Diagnostic and Interventional Cardiology (February 2018) has listed the most important of these. One of the greatest advancements has been the FDA cleared MRI-conditional models. These models allow patients to undergo MR imaging exams without harm to the device or changes to the device settings. Other improvements involve tracking device data and patient health through wireless remote monitoring systems, new data recording functionality to provide more information on patient health and device status, the introduction of singlechamber transcatheter-delivered, leadless pacemaker systems, and longer battery life and technology to help reduce pacing requirements to conserve battery power. For future pacemakers micro turbines developed by scientists in Switzerland could also play an important role. The micro turbines can be placed in blood vessels and with the help of the blood circulation they could generate electricity. The idea is to provide the pacemaker with energy without using batteries. However, today the technique can cause blood clots and it has to be developed further. NLS LITHIUM ION ELECTRON COBALT OXIDE ELECTROLYTE BARRIER PETROLEUM COKE ©Johan Jarnestad/The Royal Swedish Academy of Sciences Lithium-ion battery: Akira Yoshino developed the first commercially viable lithium-ion battery. He used Goodenough’s lithiumcobalt oxide in the cathode and in the anode he used a carbon material, petroleum coke, which can also intercalate lithium ions. The battery’s functionality is not based upon any damaging chemical reactions. Instead, the lithium ions flow back and forth between the electrodes, which gives the battery a long life. 86 NORDICLIFESCIENCE.ORG © JOHAN JARNESTAD/THE ROYAL SWEDISH ACADEMY OF SCIENCES