Components and construction of a pacemaker
Principles of myocardial excitability Myocardium is excitable not only by action potentials originating in the sinus node, but also by external electrical stimuli that drive the cells to threshold. Any stimulus driving the membrane potential to threshold will evoke an action potential , which will subsequently propagate to neighboring cells and ultimately depolarize all connected myocardium. This is the main principle behind artificial pacemakers; i.e applying an external electrical current that depolarizes cells in contact with the lead tip, and thus generate an action potential that will spread through the myocardium. Components of an artificial pacemaker Pacemakers consist of an implantable pulse generator (IPG) , which contains the electronics, a battery , and one or two leads . The pulse generator generates the electric current needed to stimulate the myocardium. The current is delivered to the myocardium via the leads, which are guided to the right atrial and ventricular myocardium via…
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Cuộc đời thì ngắn, mà nghề thì miên man;cơn bệnh phập phù;kinh nghiệm hiểm nguy, còn quyết định thì thật khó.Người thầy thuốc không phải chỉ chuẩn bị để tự mình làm đúng, mà còn khiến cho bệnh nhân, người đi theo và các yếu tố xung quanh hợp tác hài…