心电图的判读

心电图的判读,三峡大学第一临床医学院老年病科 李书国,心电图原理与心电图发展史心电图的导联心电图的现代概念与应用心电图监护的原理及与心电图的不同点常见的临床心电图判读,心电生理学发展史,1842 Matteucci C. 确定蛙心电活动1843 EDuBois-Reymond用AP描述心肌收缩1856 R V koelliker和H Muller首次在病人身上记录到心脏AP1870 G Lippmann 发明毛细管静电计(Capillary electrometer)用来测心电流,心电图学发展史,1903年荷兰莱顿大学Einthoven发明了弦线式心电图描记器，首先记录到人体心电图electrocardiogram，标志着心电学科的建立。弦线式电流计的设计原理是悬在磁铁两级间的镀银石英弦线、电流通过时，弦线会来回摆动。其方向决定于电流的方向，移动的振幅决定于电流强度，弦线摆动过程，用光源、显微放大镜，通过计时器，投影到描记的胶片上，经过冲洗才能阅读，显得不大方便。1924年，Einthoven因发明心电图而获得诺贝尔生理学和医学奖。,30年代初，弦线式心电图机才逐渐被电子管式和晶体管放大式心电图机所替代。80年代初美国Marquette公司首先推出数字化心电图机，从此，心电图进人了数字化，自动化、网络化管理的新时代。数字化心电图机的优点在于:计算机分析心电图速度快，测量数据精确，多导联同步记录，提高了工作效率，大容量存贮心电信息。,心电图学发展史,心电学理论,心肌细胞电生理离子学说 阐明了心肌细胞的电生理特性、动作电位的产生原理与心电图的关系，使心电学的理论进展到分子与离子水平，也阐明了药物作用于心脏的机制。丰富了心电图与心血管病学的内容。,心肌细胞的除极与复极,心肌细胞的动作电位与心电图,心室肌细胞动作电位,Einthoven 原理,Einthoven原理是最先形成的重要的心电图理论。他把心脏激动过程中产生的电活动，看成一组电偶，标准导联的3条边组成1个等边三角形，心脏恰好位于等边三角形的中点，产生的电流通过组织传导到体表放置电极，通过心电图机描记出心电波形,根据三角形原理，可以任意自两个导联测定心电轴。己知=VL一VR, = VF一VR, =VF-VL,所以得+ = Einthoven原理的实际意义在于帮助判断导联线有无接错，导联标记是否正确,WiLson于40年代提出单极理论，他认为单极导联可以更准确地反映探查电极下局部心肌的电位变化情况。把探查电极置于右上肢，左上肢及左下肢，分别称为VR,VL,VF导联，负极与中心电端连接。单极肢体导联描记出来的心电波幅较小，不便于分析测量。1942年，Goldberge:在此基础上稍加改进，描记出来的心电波形振幅增大50%,而又不影响Wilson提出的单极导联的特性，称为加压单极肢体导联aVR,aVL,aVF。导联表达方式:aVR探查电极置于右手腕，中心电端与左手和左下肢相连;aVL探查电极置于左手腕，中心电端与右上肢和左下肢相连;avF探查电极与左下肢连接，中心电端与两上肢相连。,ECG导联体系,自人体体表任意两点放置电极都能描记出心电图，因此产生了一百多种心电图导联体系。各国公认的是应用已久的常规12导联体系: 1903年，Einthovcn发明的标准导联I,， 1940年，Wilson与1942年Goldberger完善的加压肢体导联aVR,aVL,aVF与胸导联Vl,V2、V3,V4、V5、V6必要时加做V7,V8,V9,V3R,V4R与V5R导联,肢体导联的导联轴与六轴系统,LOCATION OF CHEST ELECTRODES IN 4TH AND 5TH INTERCOSTAL SPACES,V1: right 4th intercostal spaceV2: left 4th intercostal spaceV3: halfway between V2 and V4V4: left 5th intercostal space, mid- clavicular lineV5: horizontal to V4, anterior axillary lineV6: horizontal to V5, mid-axillary line,Wilson采用的单极胸前导联V，一直沿用至今。他认为V1, V2导联比较单纯反映右心室的电位变化，V3导联反映了过渡区电位变化。V4一V6导联反映了左心室的电位变化。,Conduction System,Katrina Kardos, MDPGY-3Albany Medical Center,Is This 12 Lead ECG normal or abnormal?,“P”波波型特点是否正常： 、aVF、V4-V6直立，aVR导联倒置，其他导联随便。,床旁心电监护的应用,定时观察并记录心率、心律、血压、呼吸、血氧饱和度观察是否有P波，P波形态、电压、时间观察PR间期，QT间期观察QRS和T波形态和时间是否有异常波形出现,常见的临床心电图判读,正常心电图,心电图的测量,心肌缺血及心电图改变,LVHLBBBRBBB,Pericardial type,ISCHEMIA,ST segment depression,David Arnall, Ph.D., P.T. (2000),Regions of the Myocardium,InferiorII, III, aVF,LateralI, AVL, V5-V6,Anterior / SeptalV1-V4,PED 596,Location of infarct combinations,LATERAL,ANTPOST,ANT SEPTAL,ANTLAT,INFERIOR,aVR,V1,V4,I,II,III,aVL,aVF,V2,V3,V5,V6,Poor myocardial protectionIncomplete revascularizationTechnical problem with graft (Kink, Twist)Air embolism,ST segment depression,Poor myocardial protectionIncomplete revascularizationTechnical problem with graft (Kink, Twist)Air embolism,ST segment depression,Poor myocardial protectionIncomplete revascularizationTechnical problem with graft (Kink, Twist)Air embolism,ST segment depression,Poor myocardial protectionIncomplete revascularizationTechnical problem with graft (Kink, Twist)Air embolism,ST segment depression,ST segment Elevation,Acute MIPoor myocardial protectionIncomplete revascularizationTechnical problem with graft (Kink, Twist, Dissection)Air embolismPreoperative Sequella,ST segment Elevation,ECG: MI Evolution,OR,CSU, 3 Wks,Katrina Kardos, MDPGY-3Albany Medical Center,Coronary Air embolism (+ valve surgery)Reperfusion (coronary surgery)Reversible,Diffuse ST segment Elevation,Diffuse ST segment Elevation,Diffuse T wave Elevation,HyperkalemiaRenal failure,Diffuse T wave Depression,Digoxin,Rhythm abnormalities,Atrial level,Atrial fibrillation / Flutter,Valvular heart disease (+ mitral valve)Manipulation of right atrium (canulation)Electrolyte disturbancesHypovolemiaHyperthyroidism,Atrial fibrillation / Flutter,Valvular heart disease (+ mitral valve)Manipulation of right atrium (canulation)Electrolyte disturbancesHypovolemiaHyperthyroidism,Sinus tachycardia,Awake patient ( + Hypertension)HypovolemiaHypoxiaHyperthyroidism,Supraventricular tachycardia,Abnormal rhythm after weaning from CPBMay be poorly toleratedAmiodarone,Rhythm abnormalities,Ventricular level,Ventricular fibrillation,Mechanical arrestGreat O2 consumption +Before CPB: critical ischemia (Left main, severe CAD)During CPB: poor myocardial protectionOn weaning from CPB: ReperfusionAfter CPB: Myocardial ischemia, electrolyte disturbances,PVC,paired,PVC (ESV),Triplet,PVC (ESV),PVC (ESV),Ventricular tachycardia,Mechanical arrest or severe hypotensionGreat O2 consumption +Before CPB: critical ischemia (Left main, severe CAD)After CPB: Myocardial ischemia, electrolyte disturbanceselectroshock,Conduction abnormalities,Sinus bradycardia,Beta-blockersCalcium Channel blockers,Katrina Kardos, MDPGY-3Albany Medical Center,Conduction System,His Bundle,R Bundle,L Bundle,Katrina Kardos, MDPGY-3Albany Medical Center,RBBB,Preoperative: Normal (10%), RVHNew RBBBpoor RV myocardial protection (imperfect retrograde cardioplegia)incomplete revascularization to RCATechnical problem with graft (Kink, Twist) to RCAAir embolism in the RCA ostium (+ valve surgery)Lesion to conduction tissues (tricuspid),1st Degree AV block,Beta blockersFrequent in elderlyAV node (valve surgery, MI),2nd Degree AV block type 1,Lesion to conduction tissues (AVR, MVR, TVR),2nd Degree AV block type 2,Lesion to conduction tissues (AVR, MVR, TVR),3rd Degree AV block,Lesion to conduction tissues (AVR, MVR, TVR),心电图的诊断步骤,总的阅读 ： 1、导联的数目： 2、各导联的标记是否正确。 3、各导联在粘贴时，是否有上下倒置的情况。 4、有无导联线错接的情况。最常见的是左、右上肢导联线反接后，可表现为假性“右位心”。 5、所记录的心电图是否有伪差。,心电图的诊断,必要的测量： 1、P波的振幅 2、P波的时程 3、PP间期，进而推算心房的频率（房率） 4、PR间