1. Liaoning Medical University Affiliated First Hospital
Electrocardiogram
ECG
Liaoning Medical University Affiliated First Hospital
He Xin

2. 一、Basic knowledge of ECG

3. Content 1、Electrophysiology 2、ECG Waveforms andintervals
3、ECG Lead system

4. 1、Electrophysiology
---Depolarization and repolarization ---Vector and vectorcardiogram

5. Pacing and conducting system of the heart
2、ECG Waveforms and intervals
Pacing and conducting system of the heart
Sinus node Internodal tracts AV node 
right bundle branch (RBB) Purkinje fibers
Bundle of His
anterior fascicle
left bundle branch (LBB) Purkinje fibers
posterior fascicle

6. Componcents of the conduction system
SA Node
Bundle of AV junction
AV Node
Bundle of AV
Left BundleBranch
Right BundleBranch

7. 3、ECG Lead system
--bipolar leads（Standard leads）I, II, III --unpolar leads: aVR, aVL, aVF

8. 3、ECG Lead system
--Chest leads: V1, V2, V3, V4, V5, V6

9. 二、 Measurement and Normal ECG

10. 1. Measurement of ECG
ECG paper Paper speed：25mm/s；Standard calibration： 1mV=10mm

11. (1) Measuring heart rate (HR)60 60
=HR
=75/min
R-R (S)
0.80S
---Measuring heart rate (HR) = 60/R-R (bpm)
---300/the number of large time units between R-R
/the number of small time units between R-R

12. (2) Amplitude of waves or segment: P, QRS, S-T, T, U

13. (3) Width or duration of waves: P, QRS, T, U
(3) Width or duration of waves: P, QRS, T, U * Duration of intervals: P-R, Q-T * Shape of waves: P, QRS, T

14. (4) Mean QRS axis
---normal cardiac axis range from -3090
---significant left deviation: -30-90
---right deviation: 90180
---significant right deviation: 180-90

15. (5) Clockwise and counterclockwise rotation ---Clockwise rotation
V1V2
V3V4
V5V6
Clockwise rotation
normal
Counterclockwise rotation
(5) Clockwise and counterclockwise rotation
  Clockwise rotation
---Counterclockwise rotation  

16. 2、 Normal ECG
(1) P wave: atrial depolarization ---Amplitude  0.20 mv ---Duration  0.11 sec ---Positive in I, II, aVF, V4-V6; Negative in aVR (2) PR interval: the time for intraatrial, --- AV nodal, and His-Purkinje conduction, --- Duration: 0.12 ~ 0.20 sec

17. (3) QRS complex: ventricular depolarization ---The width: 0. 060
(3) QRS complex: ventricular depolarization ---The width: 0.060.10 sec,  0.11 sec. ---From V1 to V6, the R waves gets bigger and bigger,the S waves gets smaller and smaller. --R/S < l in V1, but R/S > l in V5 --R in V5 and V6 < 2.5 mv, R in V1 < 1.0 mv ---R in aVR < 0.5 mv, R in aVL < 1.2 mv and R in aVF < 2.0 mv R in I < 1.5 mv ---Q < 0.04 sec in width, < 1/4 R in the same lead.

19. (4) ST segment: it reflects Phase 2 of the action potential
(4) ST segment: it reflects Phase 2 of the action potential. ---ST elevation < 0.3 mV in V1、V2； < 0.5 mV in V3；< 0.10 mV in V4  V6 ---ST depression < 0.05 mV in any leads (5) T wave: repolarization of ventricles ---It is upright in all the unipolar leads except aVR, and occasionally V1. ---T wave > 1/10 R in the same lead, maybe < 1.21.5 mV in the precordial leads

20. (6) QT interval: the duration of depolarization and repolarizaion of ventricles The normal range is 0.320.44 sec (7) U wave: the wave following the T wave and is usually very smal ---Its cause is not completely understood ---Elevated U wave: low K+ in plasma

21. 三、Atrial Enlargement and Ventricular Hypertrophy

23. 1、Atrial Enlargement (1) Right Atrial Enlargement Lead II
---P wave is peaked (P "pulmonale");
---Amplitude of P wave ≥0.25 mV in limb leads.
Lead V1
---upright and amplitude ≥0.15 mV;
---biphasic and amplitude ≥0.20 mV

26. (2) Left Atrial Enlargement
Lead II
--- Duration of P wave ≥0.12 sec
---P wave become bifid (P "mitrale")
---The distance of two peak ≥ 0.04sec
Lead V1
---P wave become biphasic
---Ptfv1  mm·sec

29. (3) Biatrial Enlargement
Lead II
P wave duration and amplitude
both increased

30. 2、Ventricular Hypertrophy
(1) Left Ventricular Hypertrophy
A. Increased voltage
---Rv5 or Rv6 > 2.5 mV
SV1 + R V5 >3.5mV (female) or > 4.0mV (male)
---RI >1.5mV；RaVL >1.2mV；RaVF >2.0 mV
RI + SIII >2.5 mV
B. Left axis deviation
C. longer duration of QRS ( s)
D. ST depression and T inversion in V5-6

33. (2) Right Ventricular Hypertrophy
A. Increased voltage (adults over 30)
---R/S ratio in V1 ≥ 1.0; R /Rs
---R/S ratio in V5 or V6 ≤ 1.0
---R/q or R/S ratio in aVR≥1
--R V1+ S V5 >1.05mV (severe>1.2mV)
--RaVR>0.5mV
B. Right axis deviation ≥ (severe > +1100)
C. ST depression and T inversion in V1-2

36. (3) Biventricular Hypertrophy
---Normal ECG.
---One ventricular hypertrophy.
---Biventricular Hypertrophy.

37. 四、Myocardial Ischemia and Myocardial infarction

38. 1、Myocardial Ischemia Subendocardial: Upright T wave
Subepicardial: Inverted, diphasic, low T wave

39. 1、Myocardial Ischemia Subendocardial: ST segment depression
Subepicardial: ST segment elevation( coronary spasm)

43. Summary ---ST segment depression ---ST segment elevation
---T wave tall positive
---T wave inversion
These changes are transitory and mostly
synchronous with symptoms

44. 2、Myocardial infarction
(1) Basic changes
---Ischemic T Waves. Tall peaked T waves, often appear as the earliest ECG sign of acute MI
---Injuried ST-segment Elevations. The ST segment elevated in one or more leads and may be straightened and fuse with the T wave (mono-phasic curve)
---necrotic (Pathologic) Q Waves. the sudden developed Q wave may indicate an acute MI -

46. (2) Progressive ECG changes
---Hyperacute changes
---Acute period
---Subacute period (T Wave Changes)
The elevated ST segments return to the baseline, and deep symmetrical T waves appear in these leads. Tall, symmetrical, upright T waves will appear in reciprocal leads at the same time
---Old myocardial infarct
A definitive diagnosis of old myocardial infarct depends on the presence of a pathological Q wave

48. (3) Localization of the ECG patterns
Leads with Abnormal Q Waves location of MI
V1  V Anteroseptal
V3  V Anterior
I, aVL, V5  V Lateral
V1  V Extensive Anterior
II, III, aVF Inferior

49. I II III aVR aVL aVF V1 V2 V3 V4 V5 V6
LOCALIZATION OF MI I II
III
aVR
aVL
aVF
V1 V2
V3 V4
V5 V6
inferior
anterior
anteroseptal
lateral
Extensive anterior

50. Anterior MI

51. Inferior MI

52. Lateral MI

53. 五、Arrhythmia

54. 1、Classification Abnormal origin Abnormal conduction
----sinus arrhythmia *
----ectopic rhythm ---passivity --escape
---initiative --premature contraction *
--tachycardia*
--flutter and fibrillation*
Abnormal conduction
----physiological block:
----pathological block: S-AB; A-VB*; LBBB; RBBB
----accessory pathway: pre-excitation syndrome

55. 2、Electrophysiology ---Automaticity ---Excitability
--Absolute refractory period (200ms)
--Effective refractory period (210ms)
--Ralative refractory period (50-100ms)
---Conductivity

56. 3、SINUS RHYTHM AND SINUS ARRHYTHMIAS
---Sinus rhythm features
---Sinus Bradycardia
---Sinus Tachycardia
---Sinus arrhythmia
---Sinus arrest
---Sick Sinus Syndrome (SSS)

57. Sinus rhythm features (1) Every P wave is following by a QRS complex
(2) P wave is upright in lead I, II, aVF, V4-V6, inverse in aVR
(3)  P-R interval ≥ 0.12sec
(4)  Normal rate is beats/min

58. Sinus Bradycardia (1) Sinus rhythm (2) Heart rate <60bpm
(R-R interval or P-P interval >1.0 sec )

59. Factors associated with sinus bradycardia
(1) Physiologic Laborers and trained athletes Emotional states leading to syncope (2) Pathologic -blocker Hypothyroidism

60. Sinus Tachycardia (1)Sinus rhythm, rate > 100 bpm
The R-R interval (or the P-P interval) <0.60 sec
(2)P-R and Q-T interval are shorter than usual
(3)S-T segment is slight depression, T waves may
be flattened

61. Factors associated with sinus tachycardia
(1) Physiologic Exercise Strong emotion Anxiety states (2) Pathologic Fever Hemorrhage Anemia Myocarditis Hyperthyroidism

62. Sinus arrhythmia ---Sinus rhythm and PR interval,
---Difference of P--P interval > 0.12sec
in the same lead

63. Sinus arrest
The P wave missed for a short time

64. Sick Sinus Syndrome (SSS)
(1)   Sinus bradycardia (HR<50/min)
(2)   Sinus arrest or SA block
(3)  Tachycardia: Atrial tachycardia
Atrial Flutter
Atrial fibrillation
(4) AV block

65. 4、Premature contractions
--- Premature Ventricular Complex
--- Premature Atrial Complex
--- Premature junctional complex

66. Premature Ventricular Complex
(1) Ventricular complex (QRS) is not preceded by a premature P' wave (2) Premature QRS complex is the wider and the bizarre , Duration of QRS> 0.12 sec T wave in direction is opposite to QRS complex (3) Complete compensatory pause

67. bigeminy
trigeminy

68. Premature Atrial Complex
(1) The premature P' wave differs in contour from the normal P wave in the same lead (2) The P'-R interval >0.12s (3) There may be a noncompensatory pause

69. Premature junctional complex
(1) A premature normal-appearing QRS complex (2) The junctional P wave (P’) may be appear before in, and after the QRS (3) Usually a complete compensatory pause

70. 5、Tachycardia Reentry Requires: ---Two conducting pathways
---Unidirectional block in one
---Slow conduction in the other
--Paroxysmal supraventricular tachycardia
--Ventricular Tachycardia
--Nonparoxysmal Tachycardia
--Torsde de pointes

71. Paroxysmal supraventricular tachycardia (PSVT)
---Heart rate between 160 – 250 bpm ---A precisely regular rhythm with normal QRS

74. Ventricular Tachycardia
---The rate is 140200/min and the rhythm is very slightly irregular ---QRS complex is the wider and the bizarre, Duration of QRS >0.12 sec ---P wave dissociated from QRS The rate of P wave is less than The rate of QRS ---Ventricular capture ---Fusion beats are present

76. Nonparoxysmal Tachycardia
---Nonparoxysmal junctional Tachycardia
The heart rate is 70130/min
---Nonparoxysmal ventricular Tachycardia
The heart rate is 60100/min

77. Torsde de pointes

78. 6、Flutter and Fibrillation
--- Atrial Flutter
--- Atrial Fibrillation
--- Ventricular Flutter
--- Ventricular fibrillation

79. Atrial Flutter
---Absence of normal P waves ---P waves replaced by saw-tooth flutter wave (F waves) ---Flutter waves seen best in leads II, III,aVF ---F waves always uniform in size,shape and frequency and absence of isoelectric line between F waves ---Regular atrial rhythm with a rate of /min ---Ventricular response of 1:1,2:1,3:1,4:1 or higher

81. Atrial Fibrillation
---Absence of clear P waves ---P waves replaced by f waves ---f waves: irregular in size, shape, best seen in lead V1 ---Rate of f waves is /min ---Irregularly irregular ventricular rate ---Generally, duration of QRS complex <0.12sec

84. Ventricular Flutter Ventricular flutter:
It is impossible to separate the QRS complexes
from the ST segment and the T waves

85. Ventricular fibrillation
The ECG shows fine or coarse waves that are
rapid, and irregular in size, shape, and width 85

86. 7、Conduction Disturbances
---A-V Block
--- Complete Right Bundle Branch Block
--- Complete Left Bundle Branch Block
--- Wolff-Parkinson-White Syndrome (pre-excitation syndrome)

87. A-V Block First Degree A-V Block Prolonged P-R interval:
P-R interval > 0.20sec. in adults (varies with
heart rate)

88. Second Degree A-V Block
Mobitz type I (Wenckebach phenomenon) ---The pattern is a progressive prolongation of the P-R interval until a beat is dropped ---The first beat after the pause has the shortest P-R interval, which may or may not be normal

90. Second Degree A-V Block
Mobitz type II
There is a fixed numerical relationship between atrial
and ventricular impulses, which may be 2:1 (2 atrial
beats to one ventricular beat) or 3:1 or 4:1

91. Third Degree A-V Block (Complete heart block)
---The atrial and the ventricular rhythms are absolutely, independent of one another (There is no relationship of P to QRS.) ---atrial rate > ventricular rate QRS is 0.12 sec. or greater

93. Complete Right Bundle Branch Block
---Right axis deviation
---QRS≥0.12 sec
---rsR’ pattern (M pattern ) in V1 or V2
---Wide and slurred S wave in leads 1, V5
and V6
---ST-T changes in leads V1 and V2

95. Complete Left Bundle Branch Block
---Left axis deviation ---A wide, slurred R in I,V5 ,V6. The wide, aberrant QRS , QRS≥0.12 sec ---The QRS in V1 may be QS or rS type ---ST-T changes

97. Wolff-Parkinson-White Syndrome (pre-excitation syndrome)
---P-R interval <0.12 sec
---QRS complex interval >0.12 sec
---Delta wave in the lower third of
theascending limb of the R wave
---ST-T changes

99. WPW Type A
characterized by dominantly upright QRS
complexes in the right precordial leads,
resulting in tall delta-R waves in leads V1
and V2

100. WPW Type B
characterized by dominantly negative QRS
complexes in the right precordial leads, with
tall delta-R waves in leads V5 and V6

101. THANK YOU !