Chapter 1 Basic Principles of Pacing
The aim of this chapter is to give sufficient background and information about cardiac pacemakers to allow interpretation of ECGs and telemetry strips of normal pacemaker behavior; to understand the indications and utility of a cardiac pacemaker; to be familiar with the coding system by which pacemaker modes are determined; to know what a paced ECG looks like and to be familiar with the different types of emergency pacing.
本章旨在描述起搏器基本知识，以便解释起搏心电图、远程心电图，了解起搏器的应用与适应证，熟悉起搏器编码系统及其起搏模式，认识各种包括紧急起搏的起搏器心电图。
一、What's the pacemaker？什么是起搏器？
A pacemaker refers a medical artificial device which delivers electrical impulses through electrodes to stimulate the heart in order to regulate its rate and rhythm. It is primarily used to treat severe bradycardia resulted from abnormal sinoatrial node function or impaired or absent conduction through the atrioventricular node. modern artificial pacemakers are programmable externally and selectable modes for the individual patient. a pacemaker and defibrillator can be assembled together in a single implantable device for both pacing and defibrillation. some employ multiple electrodes to stimulate different positions in the heart to improve synchronization of the cardiac chambers.何谓起搏器? 即是一种人工医学装置，通过电极释放脉冲刺激心脏以调节心率和节律。主要用来治疗因窦房结和房室结功能异常所致的严重心动过缓。当代起搏器可为每个病人做体外程序设计和选择起搏模式。起搏器和除颤器可组装一起，既可起搏又可除颤。有些且用多电极刺激心脏不同部位以达心脏同步功能。二、What are the working principles of a pacemaker？何为起搏器做功原理？ It is a process that a pacemaker delivers stimulus to depolarize a chamber or inhibits stimulation according to the indications controlled by its sensor. A single chamber pacemaker may deliver stimulation in a fixed rate. While, a pacing chamber, sensor sensing and pacing response constitute the working principle of a dual chamber pacemaker.这是一个全过程，即起搏器根据其感知器指令释放刺激除极心腔，或抑制刺激。单腔起搏器可能按固定频率释放刺激， 而双腔起搏器的做功原理由起搏心腔、感知器感知，以及起搏应答所组成。
1. Pacing chambers 起搏腔室
Where does a pacemaker pace? A pacemaker may pace either atrium or ventricle, or both. If a pacemaker paces only one chamber, it is called single chamber pacing, which is asynchronous pacing. If a pacemaker paces both the atrium and ventricle sequentially, it is considered dual-chamberpacing. It is AV synchronous pacing that has physiologically superior as the atrial contraction is restored.起搏器起搏什么部位呢？起搏器可以是心房或心室起搏，也可以是心房和心室起搏。如果起搏器只起搏一个心腔，称为单腔起搏，此系非同步起搏。如果起搏器顺序起搏心房和心室，则称为双腔起搏，系同步起搏。随着心房收缩的恢复，房室同步起搏具有生理上的优越性。How can a pacemaker know when the heart needs pacing? A sensor in a pacemaker is able to sense an intrinsic cardiac activity and respond suitably, either resulting in pacing or withhold in synchrony with the intrinsic heart rhythm.起搏器如何知道何时心脏需要起搏？起搏器里面的感知器能感知心脏固有活动，做出起搏或者保持与固有心律同步的恰当反应。How does a pacemaker have response to the sensing? Basically, a pacemaker responds to sensing in two ways by which it initiates impulses: triggering and inhibition.起搏器是如何对感知做出反应的？基本上，起搏器对感知的反应有两种方式：触发和抑制。（1） Triggering, a pacemaker paces whenever an intrinsic or paced activity is sensed. This is most commonly seen in a dual chamber pacing, in which the sensing of a sinus or paced p wave triggers the ventricular lead to pace.触发反应，即只要感知到自身激动或者起搏活动，起搏器便起搏。触发现象最常见于双腔起搏器，当感知到窦性或起搏P波时，便触发心室起搏。Inhibition, a pacemaker is inhibited to deliver pacing stimulus whenever an intrinsic beat is sensed by the sensor. Inhibition is seen in both single and dual chamber pacemakers.
抑制反应，只要自身搏动被感知，起搏器便停止起搏。此既见于单腔，也见于双腔起搏器。
三、Conduction anatomy 传导系统解剖
To understand the principles and concepts involved in cardiac pacing more thoroughly, a brief review of the anatomy and physiology of the specialized conduction system is necessary. An electrical impulse generated in the sinoatrial (SA) node depolarizes the atria to contract. The impulse then congregates upon the atrioventricular node with a short period of delay and continues spreading of the bundle branches and Purkinje's fibers to depolarize the ventricles (Figure 1-1) . The SA node, node and the His-Purkinje system are involved as the relevant anatomy for cardiac pacing. A single chamber pacemaker of atrium or ventricle can actually be considered to replace the SA or node respectively. While the sequentialpacing, or dual chamber pacemaker, is likely to be an bridge for theconduction.
为了更深入地理解与心脏起搏有关的原理和概念，有必要对传导系统的解剖学和生理学进行简要回顾。窦房结（SA）产生的电脉冲使心房除极并收缩，然后冲动再经房室结的延迟沿His束、束支及浦肯野纤维下传使心室除极(图 1-1)。窦房结、房室结、His-浦肯野系统是心脏起搏的相关解剖学基础。心房或心室的单腔起搏器可分别替代窦房结或房室结。而房室顺序起搏或双腔起搏器承载着房室传导的桥梁功能。
Chapter 2 Pacing Type
第2章 起搏类型
Pacemakers can be described for their different types according to the duration of pacing, the chamber paced, the chamber sensed, and the response of the pacemaker to the sensed impulse as well as polarities. Some of the more common types of pacemakers are listed here：temporary pacing、permanent pacing、unipolar pacing、bipolar pacing、single chamber pacing、dual chamber pacing、biventricular pacing and implantable cardioverter-defibrillator(ICD).
根据起搏器的使用期限、起搏和感知的腔室位置、对感知事件反应及起搏极性可将起搏器分为不同类型：临时起搏、永久起搏、单极起搏、双极起搏、单腔起搏、双腔起搏、双心室起搏、可植入性心脏复律除颤器（ICD)。
参考文献
1. 【起搏器心电图图谱】人民军医出版社 编著 蔡伯林
