This chapter presents a brief history of cardiac pacemakers and discusses the features of present day pacemakers. The first pacemaker devices could only externally stimulate the heart. Output voltage and stimulation rates were controlled from the front panel of the pacemaker. The electrodes were two one-inch diameter metal discs placed on the right and left sides of the chest, held in place by a rubber strap. Infection was a frequently fatal complication of these devices, and after transistors became available, the implantation of smaller fully implantable pacemaker units became possible. The first implantable device had a diameter of 55 mm and thickness of 19 mm, had two stainless steel electrodes sutured to the epicardium, and was externally rechargeable every month. The main developments during the early years were lead technology, capsule housing, and mainly battery life. The transvenous route for placing electrodes became available in 1959 and with the introduction of central vein catheterization access, non surgeons cardiologists also started to implant pacemakers. Early pacers were asynchronous with the patient's own rhythm, and were only capable of delivering an electrical stimulus to the heart at a steady rate. The next challenge in pacemaker technology was to attempt to restore atrioventricular synchrony. A bifocal pacemaker was introduced, which could pace the atria, and after an appropriate AV interval would pace the ventricle. Complications from pacemakers can be divided into the long-term effects or risks of chronic pacing as well as device-, lead-, or implantation-related complications. Device-related complications mainly include hardware failure and tissue injury from stress, infection, or allergic reactions. Pacemaker related infections may involve cardiac tissue, leads, and the cutaneous and subcutaneous tissue and their treatment options include antibiotic therapy, removal of the implanted system, and tissue debridement.
|Title of host publication||Neuromodulation|
|Number of pages||10|
|State||Published - 1 Dec 2009|
ASJC Scopus subject areas
- Clinical Neurology
- Anesthesiology and Pain Medicine