BasicECG by Dr Chareanlap

8/9/2019 BasicECG by Dr Chareanlap

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&

sinus node

AVnodeHis bundle bundle branchPurkinje fibers ventricular myocardium

electrocardiograph electrocardiogram

electrodes(ground)runleads12leads

V1 4sternumV2 4sternumV3 V2V4V4 5clavicleV5 V4anterior axillary lineV6 V4midaxillary line

V3RV1V4RV4R5clavicle


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12 leads- Bipolar limb leads 2/

Lead 1 -Lead 2 -Lead 3 -

- Unipolar limb leads voltage/central terminalLead aVR voltage (aelectrical augmentation 50% )Lead aVL voltage Lead aVF voltage

-

Chest leads voltagehorizontal plane:unipolar leadsLead V1-V6 voltageV1-V6 central terminal (indifferentelectrode)

depolarization& repolarization

leads (isoelectric line)

(isoelectric line)

QRS

Isoelectric line


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1

1mm25mm/sec 1

1/250.04sec1mV=10mm

calibration signalECGcheck paper

speed(ECG waveform) calibration signal(tracings)

Vectorcardiogram

Vector ,:,

Vectorcardiogram vectorECG


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-12-2vector

x,y,z

.....

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...

...

...

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Basic ECG

1.Rhythm

2.Rate

3.P wave

4.PR interval

5.QRS interval

6.QRS complex

7.ST segment

8.T wave

9.U wave

10.QT duration

1.Rhythmsinus rhythm2.Rate 60-100 /1 = 0.04 sec;1 = 5 = 0.2 secrate

1 rate= 1500/QRS2


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2QRS2 rate(bpm)

1

300

2

150

3 100

4 75

5 60

6 50

7 43

8

37

9 33

10 30

300 250 214 187 167 150 136 125 115 107 100

100 94 88 83 79 75 71 68 65 62 60

60 58 56 54 52 50 48 47 45 44 4343 42 41 39 38 37 37 36 35 34 33

33 33 32 31 31 30

3 rate = cardiac cycles 5 secs x 123.P wave

- atrial depolarization

SA noderightatrium&left atrium vector - 0.12sec- lead 1,2,V4-V6,aVFlead aVR

- variable in 3,aVL,other chest leads


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4.PR interval

- atrial depolarization(P wave)delayAV junctional area(AVnode&His bundle)

- 0.12-0.20sec(3-5)5.QRS interval

- ventricular depolarization;0.06-0.10sec(1-2)6.QRS complex

-Normal Q 0.03 sec

-Q 1-2mm lead 1,aVL,aVF,V5,V6

-Deep QS or Qrlead aVR-QS lead 3,V1,V2

QRS axis

-

QRS axis normal 0-90 degree(QRSaxis in frontal

plane)

- QRS voltage >5mm in limb leads >10mm in chest leads

- R wave progression R S wave leadV3-V4(transition zone)

QRS axis


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Rate

P waveupright in 1,2,V4-V6,aVF inverted in aVR;variable in 3,aVL,other chest leadsP1 lead- P(QRS) positive in aVR;negative in aVL,1

DDX 1.

electrodes

2.dextrocardia wih situs inversus(V1-v6)3.ectopic atrial or AV junctional rhythm

P2 Left atrial enlargement mitral stenosis2- P mitrale P wave>3mm(0.12sec) notching(significant if peak to peak >

0.04sec)in limb leads- diphasic in V1negative(>1mm)

left atrial abnormality

P3 Right atrial enlargementCOPD,pulmonary HT

-

P pulmonale tall,peaked P wave>2.5mmlimbprecordial leads

PR interval

= 0.12-0.20 sec


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PR1 First degree AV block

- PR interval>0.20sec prolonged PR interval-

prolonged PR interval 1.First degree AV block

2.Trifascicular block(eg. CRBBB,LAHB,prolonged PR interval=delayed conduction inposterior fascicle)

3.Hyperthyroidism 4.Normal variation

PR2 Short PR in WPW syndrome

- PR interval


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3.Lown-Ganong-Levine syndrome(LGL syndrome)

4.glycogen storage disease type II(Pompes)

5.HT 9. Duchenne muscular dystrophy6.normal variation 10.HOCM

7.Fabry,s disease

8.pheochromocytoma

Note:PR segment= end of P beginning of QRS

isoelectric displaced in atrial infarction,acute pericarditis


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QRS complex

interval = 0.06-0.10 secQRS1 Low voltage

- average voltage in limb leads26mm

3.R in 1 + S in 3 >25mm

4.R + S in any V lead >45mm

5.R in aVL >11mm

6.R in aVF >20mm

7.R in aVL+S in V3 >28mm > 20mm (Cornell)

QRS3 Right ventricular hypertrophy

-

R>S in lead V1,V2 (tall R)

-

right axis deviation


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tall R wave in V1 1. WPW syndrome (QRS widening &Short PR interval,Delta waves (which may be positive or negative))

2. RBBBB

3. RVH

4. Posterior infarction (evidence of inferior MI;mirror image in V1,V2)

5. Normal variant


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QRS5 Acute MI

A subendocardial ischemiaB transmural ischemia

ECGAcute MI:hyperacute T(peaked T wave)STelevation(convex)Q waveinverted TSTisoelectric lineQ


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2Q inverted T,

myocardial infarctionseptal V1-V2

anterior V3-V4

anteroseptal V1-V4

extensive anterior V1-V6

lateral V6,1,aVL

high lateral 1,aVL

anterolateral V3-V6,1,aVL

inferior 2,3,aVF

RV infarct ST elevation1mm in V4R-V6R

...

...


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Reciprocal changes ECG primarychangesinfarct "ST segmentelevation and T wave inversion" reciprocal changes "ST segmentdepression and tall pointed T waves",

Inferior limb leads(II,III,aVF) precordial leads lead I,aVL

Q wave (10,11)

ECG Q wavemyocardial infarction(1-9)


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QRS6 Left bundle branch block

- RSRin V5,V6,1,aVL

- Slurred S in V1,V2

- QRS duration >0.10sec and 0.12sec in complete LBBB

- ST depression and inverted T secondary ST-T changes


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QRS7 Right bundle branch block

-

RSRin V1,V2

- Slurred S in V5,V6,1,aVL

- QRS duration >0.10sec and 0.12sec in complete RBBB

- ST depression and inverted T secondary ST-T changes


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QRS8 Left axis deviation

- QRS axis > -30

QRS9 Right axis deviation

-

QRS axis>90

ST segment

ST1 Acute pericarditis- ST elevationconcavechest&limb leads STinverted T

clue PR segment depression- MIpericarditisQ wave ST elevationlead1&3

reciprocal change


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ST2 myocardial ischemia

- ST depressionhorizontal or downslope at least 1mm symmetricalinverted T

ST3 Secondary ST-T changes in Ventricular hypertrophy,BBB

-

ventricular hypertrophy,bundle branch block- ST depression and inverted Tlead

-

lead V1,V2,(V3) RVH,RBBB- lead V4,V5,V6 LVH,LBBB

ST4 Digitalis effect

- concave ST depressionsagging,flattening and inversion of T wave in leads with tallR waves(leads negative QRS subendocardial ischemia digitalis) J point depressionNote:digitalis effect(not toxicity)ST depression with inverted T and prolonged PR

ST5 Early Repolarization

T wave

upright lead1,2,V3 to V6 ,inverted in lead aVRvariable in lead 3,aVL,aVF,V1,V2(inverted T in V1,V2 )


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T wave 5mm in limb leads 10mm in chest leadsT1 Hyperkalemia

- tall peaked symmetrical T wave prolongationPR interval,QRSduration P wave sine waveflat lineelectrical activity

T2 Myocardial ischemia

- deep symmetrical inverted T wave subendocardial ischemia

T3 Early acute MI

- hyperacute T(T wave)ST elevation


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T4 Secondary T wave change

- ST depression ventricular hypertrophy,bundle branch blockT5 Non specific T wave change

- T wave inversion criteria

Tall T wave

1.myocardial infarction

2.hyperkalemia

3.some myocardial ischemia

4.LV diastolic overloading (tall uprightT and tall R in V5,V6)eg.AR,MR,PDA

5.psychotics

6.CVA

T wave inversion

1.ischemia

2.pericarditis

Note:chronic constrictive pericarditis

low voltage and inverted T wave

3.non specific

4.secondary T wave changes(STdepression) :BBB, hypertrophy

5.digitalis effect(concave ST depression)6.myxedema(low voltage and low toinverted T wave)


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QT interval

QTc 0.44 sec; QTc = QT/RR intervalQT1 Prolonged QT

- prolonged QT(rough estimation QT interval> half of RR interval;HR65-90bpm) predisposeTorsade de Pointes(syncope) sudden cardiac death

prolonged QT(14) 1.Congenital long QT syndrome: Romano-Ward sydrome, Jervell-Lange-Nielsen

syndrome, Refsum syndrome

2.Drugs:quinidine,procainamide, flecainide, encainide, Tetracyclic/tricyclic

antidepressant,phenothiazines,etc.(13)

3.Electrolyte imbalance: hypocalcemia, hypomagnesemia (hypokalemia

prolonged QT flattening T, prominent U U wave QT interval )(12)4.Rheumatic fever/rheumatic heart disease

5.Myocarditis

6.Cerebrovascular occlusive disease,traumatic brain injury,subarachnoid

hemorrhage,encephalitis

7.Ischemic coronary heart disease

8.Congestive heart failure


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9.Hypothermia

10.Stringent dieting

11.mitral valve prolapse

QT2 Shortened QT

- QT interval 0.30sec

-

1.congenital short QT

syndrome (sudden cardiac death ventricular fibrillation)2.hypercalcemia

3.potassium intoxication

4. digitalis effect

U wave

lead V2-V4,0.2mVU1 Prominent U in hypokalemia

- prominent U wave T wave leadV4-V6 ST depression,Twave

1.

http://www.nursingcenter.com/library/JournalArticle.asp?Article_ID=751949


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2. Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care .

Philadelphia: Elsevier/Mosby; 2005.

3. Wagner GS. Marriott's Practical Electrocardiography . 10th ed. Philadelphia: Lippincott Williams & Wilkins; 2001.

4. Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular

Medicine . 7th ed. Philadelphia: Elsevier Saunders; 2005.

5. Sreeram N, Cheriex EC, Smeets JL, Gorgels AP, Wellens HJ. Value of the 12-lead electrocardiogram at hospital

admission in the diagnosis of pulmonary embolism. Am J Cardiol . 1994;73:298303.

6. Geibel A, Zehender M, Kasper W, Olschewski M, Klima C, Konstantinides SV. Prognostic value of the ECG on

admission in patients with acute major pulmonary embolism. Eur Respir J. 2005;25:843848.

7. Goldberger AL. Pathogenesis and Diagnosis of Q Waves on the Electrocardiogram . In: Rose BD, ed. UpToDate

. Waltham, MA; 2006. www.uptodate.com .

8.

Marriott HJL. Pearls and Pitfalls in Electrocardiography . Philadelphia: Lea & Febiger; 1990.

9. Marafioti V, Variola A. Pseudoinfarction pattern by misplacement of electrocardiographic precordial leads. Am J

Emerg Med . 2004;22:62.

10.Goldberger, AL. Myocardial infarction: Electrocardiographic differential diagnosis, 4th ed. Mosby Year Book, St

Louis, 1991.

11.http://cmbi.bjmu.edu.cn/uptodate/electrocardiography/General%20electrocardiography/Pathogenesis%20and%

20diagnosis%20of%20Q%20waves%20on%20the%20electrocardiogram.htm

12. Jones, E. Hypokalemia. NEJM 2004;350: 1156

13.

http://www.qtsyndrome.ch/drugs.html

14.http://www.jeffmann.net/NeuroGuidemaps/syncope.htm

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BasicECG by Dr Chareanlap