1、苏州大学附属二院心内科苏州大学附属二院心内科 邵春来邵春来Griffith Joyner38 years old died in 1998Vivian fu 28 years old died in 2003Marco Pantani35 years old died in 20041.2.3.4.Deplaorization Sequence of a“Strip”of 5 Myocardial CellsDepolarization progressing from left to right2.when depolarization spreads away from any lead,
2、it produces a negative(downward)deflection in that lead.1.when depolarization spreads toward any lead,it produces a positive(upward)deflection in that lead.3.when depolarization spreads firstly toward and then away from any lead,it produces a biphasic deflection.MagnitudeDirectionfrom 0resultant 0ax
3、ileargument Vectors may be summed by parallelogram method to produce Resultant Vector=Translate=SummedResultant VectorSA nodeAV node两结之间用vector表示1342SA nodeAV node运用4原则记录心脏的vector传导过程位置不重要12341342不同部位记录电极的电位Various patterns of the ECG can be obtained from the same vector loop.The pattern depends on
4、the position of the electrode.PTQRSfrontal plane frontal plane transverse plane Lead v1:4th intercostal space just to the right of the sternumLead v2:4th intercostal space just to the left of the sternumLead v3:a line midway between lead V2 and V4Lead v4:the mid-clavicular line in 5th intercostal sp
5、aceLead v5:the anterior axillary line at the same level as lead V4Lead v6:the mid axillary line at the same level as lead V4angle of Louis Totally different patterns of the potential(ECG)can be obtained from the same cardiac cycle.The potential(ECG)pattern depends on the position of the electrodes.N
6、ow,you know,the ECG is a graphic recording of the electrical currents produced by the heart muscle during the atrial and ventricular depolarization and repolarization.In summaryStandardized Methods&Devices ECG Paper Device Paper Speed Device Calibration Electrode PlacementHorizontal AxisVertical Axi
7、sEKG Paper Standardized Methods&Devices ECG Graph Paper Vertical axis-millivolt 1 small box=1 mm=0.1 mV Horizontal axis-time 1 small box=1 mm=0.04 sec.Standardized Methods&Devices Paper Speed&Calibration Paper Speed-25 mm/sec standard Calibration of Voltage is Automatic Both Speed and voltage calibr
8、ation can be changed on most devicesWhat is the heart rate?(300/6)=50 What is QRS Axis?The QRS axis is determined by overlying a circle,in the frontal plane.By convention,the degrees of the circle are as shown.The normal QRS axis lies between-30o and+90o.0o30o-30o60o-60o-90o-120o90o 120o150o180o-150
9、oA QRS axis that falls between-30o and-90o is abnormal and called left axis deviation.A QRS axis that falls between +90o and+150o is abnormal and called right axis deviation.A QRS axis that falls between +150o and-90o is abnormal and called superior right axis deviation.Hexaxial array and ECG vector
10、s from various leads.1.Find net+or QRS in lead 12.Find net+or _ QRS in Lead aVF3.Resultant Vector.This is Mean Electrical Axis of Heart or Cardiac Vector.Electrical axis is about+60oTransitional zone(chest leads)Represents the location of the lead,having positive and negative deflections of the same
11、 magnitude.ClockwisenormalCounterclockwise Components of the ECGComponents of the ECG Complex P Wave first upward deflection represents atrial depolarization usually 0.10 seconds or less usually followed by QRS complex When the atria are excited,this depolarizing electrical current can be recorded b
12、y ECG,and it is named P wave.Components of the ECG Complex QRS Complex Composition of 3 Waves Q,R&S represents ventricular depolarization much variability usually 0.12 secComponents of the ECG Complex Q Wave first negative deflection after P wave depolarization of septum not always seenComponents of
13、 the ECG Complex R Wave first positive deflection following P or Q waves subsequent positive deflections are R,R”,etcComponents of the ECG Complex S Wave Negative deflection following R wave subsequent negative deflections are S,S”,etc may be part of QS complexComponents of the ECG Complex PR Interv
14、al time impulse takes to move through atria and AV node from beginning of P wave to next deflection on baseline(beginning of QRS complex)normally 0.12-0.2 sec may be shorter with faster ratesComponents of the ECG Complex QRS Interval time impulse takes to depolarize ventricles from beginning of Q wa
15、ve to beginning of ST segment usually 0.12 secComponents of the ECG Complex J Point point where QRS complex returns to isoelectric line beginning of ST segmentComponents of the ECG Complex ST Segment early repolarization of ventricles measured from J point to onset of T wave elevation or depression
16、may indicate abnormalityComponents of the ECG Complex T Wave repolarization of ventricles concurrent with end of ventricular systoledownwardleftwardThe early portion of P wave:the right atrium.The late portion:the left atrium.It is important to remember that the P wave represents the sequential acti
17、vation of the right and left atria,and it is common to see notched or biphasic P waves of right and left atrial activation.P duration 0.12 secP amplitude 0.12s in frontal plane(usually lead II)Notched P wave in limb leads(usually lead II)with the inter-peak duration 0.04s Terminal P negativity in le
18、ad V1(i.e.,P-terminal force)duration 0.04s,depth 0.1 mv.increase the magnitude of the atrial depolarization vector and produce a tall P wave.P wave amplitude 2.5 mm in II and/or 1.5 mm in V1 Features of both RAE and LAE in same ECGP wave in lead II 2.5 mm tall and0.12s in durationInitial positive co
19、mponent of P wave in V1 1.5 mm tall and prominent P-terminal forceLeft ventricular hypertrophy(LVH)Mean QRS axisChanges in limb leads in the frontal planeTaller R wave in lead I,deeper S wave in lead III left axis deviationChanges in chest leads in the horizontal planeTaller R wave in lead v5,deeper
20、 S wave in lead v1 v5v5ST segment depression and T wave inversionLimb-lead voltage criteria:R in aVF 25 mm R in I+S in III 25 mmChest-lead voltage criteria:S in V1+R in V5 or V6 35 mm(women)General ECG features include:Right axis deviation(90 degrees)Tall R-waves in RV leads;deep S-waves in LV leads
21、Slight increase in QRS durationMay see incomplete RBBB pattern or qR pattern in V1Changes in limb leads in the frontal planeTaller R wave in lead III,deeper S wave in lead IRight axis deviationMean QRS axisRight ventricular hypertrophy(RVH)V5V5Changes in chest leads in the horizontal planeTaller R w
22、ave in lead v1,deeper S wave in lead v5 ST segment depression and T wave inversionRight axis deviation(90 degrees)Chest lead criteria:R in V1+S in V5(or V6)10 mmR/S ratio in V5 or V6 1In the presence of LVE any one of the following suggests this diagnosis:R/S ratio in V5 or V6 6 mmRight axis deviati
23、on(90 degrees)sinus rhythm and sinus arrhythmiasECG of Sinus Rhythms1).The P wave is upward in lead I,II,avF,V4-5 and downward in lead avR.2).The PR interval0.12 second.3).Heart rate between 60 and 100 rates per minute.Heart rate is less than 60 per minuteHeart rate exceeding 100 per minuteP-P or R-
24、R interval varies in duration by at least 0.12 second There is no sinus P wave in ECG suddenly.The long interval is not times of P-P interval.Technical word 联律间期联律间期(coupling interval)(coupling interval)distance from the preceding normal QRS complex to the premature ventricular beat 代偿间歇（代偿间歇（compen
25、satory pause)compensatory pause)：pause(the sum of the R-R intervals including the pre-premature beat and the post-premature beat interval equals the sum of two normal R-R intervals)1).The QRS and T waves that follow the premature P waves usually resemble the other QRS and T waves in the lead.2).The
26、P-R interval of the atrial premature beat is usually longer than the normal PR intervals in the ECG.3).An atrial premature beat is often followed by a noncompensatory pause.1.Similar to PACs in clinical implications,but occur less frequently.2.The PJC focus,located in the AV junction,The retrograde
27、P wave may appear before,during,or after the QRScomplex;if before,the PR interval is usually short(i.e.,0.12 s).Premature junctional complexesPremature junctional complexesappear after theQRS complexesbefore the QRS complexes Andafter the QRS complexesAnd 1).The QRS complex is premature,is 0.12secon
28、d or more wide.It is associated with a T wave that usually point in a direction opposite to the main deflection of the QRS complex.2).The premature QRS complex is not preceded by a P wave.3).A ventricular premature beat is often followed by a fully compensatory pauseP P Pthey originate in the differ
29、ent ectopic site PVCs may occur as isolated single events or as couplets,triplets,and salvos(4-6 PVCs in a row),also called brief ventricular tachycardias a ventricular premature beat will occur with the apex of the preceding T wave,This is R on T phenomenon.When this occurs,it may be a precursor of
30、 a ventricular tachycardia.Atrial Tachycardia Ectopic,unifocal P waves with atrial rate 250/min(not to be confused with slow atrial flutter)Ectopic P waves usually precede QRS complexes with PR interval 0.22s in old adults.Mobitz Type I(Wenckeback phenomenon)(1)The P-R interval becomes longer and lo
31、nger(2)The R-R interval gets shorter and shorter,until there is a blocked or nonconducted ventricular beat with a long pauseMobitz Type II:(1)The fixed P-R interval(2)There is a fixed numerical relationship between atrial and ventricular impulses,which may be 2:1 or 3:1 or 4:1IIIAVB(Complete heart b
32、lock)1)The atrial and the ventricular rhythms are absolutely independent of one another.2)There is no P-R to QRS relationship.3)The atrial rate is more rapid than the ventricular rate.4)regular P-P interval.5)rugular R-R intervalleft anterior fascicleleft posterior fascicle 1.Right Bundle Branch Blo
33、ck(RBBB)1).QRS 0.12 sec or wider2).Rsr(M)pattern in V1 and V2 and deep,wide S wave in,V5-6.When incomplete RBBB is present,the pattern is similar,but the QRS width is less than 0.12sec.1)QRS 0.12sec or more.2)absent q waves in I,V5 and V63)wide,notched,or slurred R waves in V5-6 with depressed ST se
34、gments,downward T waves.4)wide QS or rS patters with elevated ST segments and upward T waves in V1-2.When incomplete LBBB in present,the pattern is similar,but the QRS width is less than 0.12 Paroxysmal Supraventricular Tachycardia1).Heart rate is regular rhythm with a rate of 160-250/minute.2).The
35、QRS complex in form is usually normal.3).The P wave in not easy to see.4).With abrupt onset and abrupt terminal.The AV node often has dual pathways;in this diagram the alpha pathway is fast,but has a long refractory period;the beta pathway is conducts more slowly,but recovers faster.In sinus rhythm
36、the faster alpha pathway is used and accounts for the normal PR interval.When a PAC occurs,however,the impulse may find the alpha pathway refractory,but able to traverse the beta pathway.When the premature impuse reaches the intersection of the two pathways,alpha may be recovered and allow retrograd
37、e activation of the atria;this may enable a reentrant tachycardia to develop.WPW综合征综合征PR间期间期0.04 s or25%of R-wave amplitudeR波ST段acute phaseQ波T波prophaseAnterior MIQs complexes in leads V2-6 plus ST-T changes)Inferior MIPathologic Q waves and evolving ST-T changes in leads II,III,aVFAnteroseptal MIQ,Q
38、S,or qrS complexes in leads V1-V3(V4),Evolving ST-T changesHigh Lateral MIQ-wave,slight ST elevation,and T inversion in lead and aVL心心 脏脏 壁壁w all血血 管管vessel相相 关关 导导 联联leadsseptum间间 隔隔LAD左左 冠冠 状状 动动 脉脉 前前 降降 支支V1、V2anterior w all前前 壁壁LAD左左 冠冠 状状 动动 脉脉 前前 降降 支支I、aVL、V2、V3、V4lateral w all侧侧 壁壁CIRC回回 旋旋
39、 支支I、aVL、V5、V6posterior w all后后 壁壁variable可可 有有 变变 异异V1、V2可可 有有 相相 应应 变变 异异（reciprocal changes）inferior w all下下 壁壁RCA右右 冠冠 状状 动动 脉脉、aVFright ventricle右右 心心 室室 RCA右右 冠冠 状状 动动 脉脉V3R、V4RThe T waves are tall,peaked and have a narrow base4.05.5mmol/L 5.5mmol/L 7.5mmol/LK+7.5mmol/LK+10 mmol/Lremember the triad of ST segment depression,low amplitude T waves,and prominent U wavesK+3 mmol/L
