Arrhythmia心律失常.ppt

Definition Arrhythmia （cardiac arrhythmia）are disorders of impulse formation and （or）conduction. The normal beat originated from sinus sinus node. Usually, the frequency of waves ranges was 60 to 100 per minute, which is regular day and night. The impulse agits auricles and ventricles through the atrioventricular conduction system(AVCS) at the normal sequence. For adults, time is fixed , usually 0.12 to 1.21 sec. Furthermore , the time of comduction from Purkinje‘s fibers to ventricular muscles is also fixed，usually less than 0.1 ms。 心律失常的定义 心律失常是指心律起源和（或）心搏传导异常。 正常心律起源于窦房结，频率范围为60次～100次/分钟，比较规则。窦房结冲动经正常房室传导系统顺序激动心房和心室。 对成人而言，传导时间是恒定的，为0.12～1.21秒。同时，冲动经浦肯野纤维到达心室肌的传导时间也是恒定的，通常小于0.10秒。 心脏解剖概图 ANATOMY OF THE CONDUCTING SYSTEM Under normal conditions, the pacemaker function of the heart resides in the sinoatrial (SA)node,which lies at the junction of the right atrium and superior vena cava . Once the impulse exits the sinus node, it traverses the atrium until it reaches the atrioventricular (AV)node. The SA node is 1.5 cm long and 2 to 3 mm wide and is supplied by the sinus node artery, which arises from either the right coronary artery (60%)or the left circumflex coronary artery (40%). The blood supply of the AV node is derived from the posterior descending coronary artery (90%). 传导系统的解剖学 正常状态下，心脏起搏功能位于窦房结，即右心房与上腔静脉的交界处。 冲动一离开窦房结，就经由心房到达房室结。 窦房结1.5厘米长，2至3毫米宽，由右冠状动脉窦房结支供养，右冠状动脉窦房结支60%起源于右冠状动脉，40%起源于冠状动脉左旋支。 ANATOMY OF THE CONDUCTING SYSTEM The AV node lies at the base of the interatrial septum just above the tricuspid annulus and anterior to the coronary sinus. The electrophysiologic properties of the AV node result in slow conduction, which is responsible for the normal delay in AV conduction。 The SA node, atrium, and AV node are significantly influenced by autonomic tone. Vagal influences depress automaticity of the SA node, depress conduction, and prolong refractoriness in the tissue surrounding the SA node。Sympathetic influences exert the opposite effect