Ecg-1
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E.C.G. Course – I The Normal E.C.G Dr. Michael Kassirer ”Dept. Internal Medicine ”D Tel-Aviv Medical center
Objective By the end of lesson 1 the student will:
Be able to review basic cardiac electro-physiology Understand how the electrical vector is formed and recorded. Know the position of the conventional frontal and axial leads, and the location of right precordial and posterior leads. Be able to identify the different deflections and intervals of the E.C.G, know their normal values, and explain what they represent. Know how to calculate the heart rate and electrical axis.
Stand on the shoulders of giants
The E.C.G - Preface
The E.C.G = Electro-Cardio-Graph is a graphic recording of the electric potentials generated by the heart. Advantages: ►Immediate availability. ►Non-invasive, Non-expensive ►highly versatile ►Diagnostic tool and therapeutic aid.
Conductive system • Pacemaker cells • Conduction tissue • myocardium
Conductive system • Sinus-Atrial Node • AV Node • Bundle of Hiss • Right Bundle Brunch • Left Bundle Branch: - Anterior fascicle - Posterior fascicle • Purkinje fibers
Cardiac electrophysiology 1
Membrane Potential: Rest: - 90mV Action: + 20mV
Depolarization: - 90mV (Na+ In) Re-polarization: +20mV (K+ Out)
+20mV - 90mV
Cardiac electrophysiology 2 20mV+
90mV-
Electrical current
---
-
-
-
- - + - + - -
+ + + + + + + + + ++ + +
+ +
+ +
+ + + + +
:The problem
How to Record 4D vector (3dD + Voltage) in 3D ??recording system
Electrical vector
Electrical Vector 0 2 4 6 8 10 12
2
4
6
8
10
12
14
16
E.C.G leads – frontal plane Bi-polar Leads:
Uni-polar leads:
E.C.G leads – frontal plane Bi-polar Leads:
Uni-polar leads:
Frontal plane - summery
Electrode position – horizontal plane
Electrode position: Frontal Plane Horizontal (precordial) plane
E.C.G – Waveforms and intervals
E.C.G – Waveforms and intervals
E.C.G paper/strip 1mV
Paper speed = 25mm/sec. Cube = 0.04 sec. 5 Cubes (large) = 0.2 sec
The P wave
)P wave = P wave )RA) + P wave )LA Normal Values: W < 0.12 sec. )3 mm) H < 2.5 mm Best seen - L2 )+) - V1 )+ or iso-electric)
The PR interval
PR interval = AV delay Normal Values: 0.1 – 0.2 sec
The QRS complex – V. depolarization
V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1
V6
L3
L2
The QRS complex – V. depolarization
V1 V1
L3
V6
L2
The QRS complex – V. depolarization
V1 V1
L3
V6
L2
The QRS complex – V. depolarization
V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1 V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1 V1 V1
V6
L3 L3
L2
The QRS complex - 1
QRS complex = Ventricular depolarization Q wave = septum - Normal in V1, aVR - L3 )disappear in inspiration). Normal Q < 0.04 sec, < 4mm Q/R ratio < 15% )V4-6), < 25% )L2, 3, aVF)
The QRS complex - 2
)R wave = R )RV) + R )LV Normal Values: W < 0.1 sec Voltage ≈ size / distance, but R )V5) < 25mm )R < S in V1 )rS or rSr’ pattern R > S in V5,6 - Transition zone in V3,4
How to find the heart ?rate HR = 300 / No. of large cubes RR interval
RR interv al
Ex. = 300 / 5 = 60
HR = 6 * (No of QRS in 6 sec.) Ex = 6 * 18 = 108
How to find the Electrical axis
How to find the Electrical axis ((method 1
QRS in L1
QRS in aVF
aVF
L3 aVF
L1 L1
How to find the Electrical axis ((method 2
1. Find the isoelectric QRS 2. The axis is 90º to it.
L1 L3 )120º+)
L 3
30º+
aVF
L3 aVF
L1
Electrical axis
Normal Axis: - 30º - +110
Right Axis deviation: > + 100
Left Axis deviation: < - 30º
The ST-T segment
ST segment = Ventricular repolarization Normal – Horizontal, Isoelectric )Normal ST elevation – High take-off )V1-3 early repolarization Concave , After deep S, or with↑↑.T
The T wave
Vector – same direction as QRS complex .ex. Rt. Precordial leads always + in I, II, aVL, V3-6 always – in aVR -
The QT interval
Normal Value - QTc ≥ 0.40msec
QTc = QT/√RR
QTc calculation QT =0.64 RR
RR = 1.24 QT
√ RR = 1.114 QTc = QT/√ RR = 0.57
Normal E.C.G - summery
Objective By the end of lesson 1 the student will:
Be able to review basic cardiac electro-physiology Understand how the electrical vector is formed and recorded. Know the position of the conventional frontal and axial leads, and the location of right precordial and posterior leads. Be able to identify the different deflections and intervals of the E.C.G, know their normal values, and explain what they represent. Know how to calculate the heart rate and electrical axis.
Stand on the shoulders of giants
The E.C.G - Preface
The E.C.G = Electro-Cardio-Graph is a graphic recording of the electric potentials generated by the heart. Advantages: ►Immediate availability. ►Non-invasive, Non-expensive ►highly versatile ►Diagnostic tool and therapeutic aid.
Conductive system • Pacemaker cells • Conduction tissue • myocardium
Conductive system • Sinus-Atrial Node • AV Node • Bundle of Hiss • Right Bundle Brunch • Left Bundle Branch: - Anterior fascicle - Posterior fascicle • Purkinje fibers
Cardiac electrophysiology 1
Membrane Potential: Rest: - 90mV Action: + 20mV
Depolarization: - 90mV (Na+ In) Re-polarization: +20mV (K+ Out)
+20mV - 90mV
Cardiac electrophysiology 2 20mV+
90mV-
Electrical current
---
-
-
-
- - + - + - -
+ + + + + + + + + ++ + +
+ +
+ +
+ + + + +
:The problem
How to Record 4D vector (3dD + Voltage) in 3D ??recording system
Electrical vector
Electrical Vector 0 2 4 6 8 10 12
2
4
6
8
10
12
14
16
E.C.G leads – frontal plane Bi-polar Leads:
Uni-polar leads:
E.C.G leads – frontal plane Bi-polar Leads:
Uni-polar leads:
Frontal plane - summery
Electrode position – horizontal plane
Electrode position: Frontal Plane Horizontal (precordial) plane
E.C.G – Waveforms and intervals
E.C.G – Waveforms and intervals
E.C.G paper/strip 1mV
Paper speed = 25mm/sec. Cube = 0.04 sec. 5 Cubes (large) = 0.2 sec
The P wave
)P wave = P wave )RA) + P wave )LA Normal Values: W < 0.12 sec. )3 mm) H < 2.5 mm Best seen - L2 )+) - V1 )+ or iso-electric)
The PR interval
PR interval = AV delay Normal Values: 0.1 – 0.2 sec
The QRS complex – V. depolarization
V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1
V6
L3
L2
The QRS complex – V. depolarization
V1 V1
L3
V6
L2
The QRS complex – V. depolarization
V1 V1
L3
V6
L2
The QRS complex – V. depolarization
V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1 V1 V1
V6
L3 L3
L2
The QRS complex – V. depolarization
V1 V1 V1
V6
L3 L3
L2
The QRS complex - 1
QRS complex = Ventricular depolarization Q wave = septum - Normal in V1, aVR - L3 )disappear in inspiration). Normal Q < 0.04 sec, < 4mm Q/R ratio < 15% )V4-6), < 25% )L2, 3, aVF)
The QRS complex - 2
)R wave = R )RV) + R )LV Normal Values: W < 0.1 sec Voltage ≈ size / distance, but R )V5) < 25mm )R < S in V1 )rS or rSr’ pattern R > S in V5,6 - Transition zone in V3,4
How to find the heart ?rate HR = 300 / No. of large cubes RR interval
RR interv al
Ex. = 300 / 5 = 60
HR = 6 * (No of QRS in 6 sec.) Ex = 6 * 18 = 108
How to find the Electrical axis
How to find the Electrical axis ((method 1
QRS in L1
QRS in aVF
aVF
L3 aVF
L1 L1
How to find the Electrical axis ((method 2
1. Find the isoelectric QRS 2. The axis is 90º to it.
L1 L3 )120º+)
L 3
30º+
aVF
L3 aVF
L1
Electrical axis
Normal Axis: - 30º - +110
Right Axis deviation: > + 100
Left Axis deviation: < - 30º
The ST-T segment
ST segment = Ventricular repolarization Normal – Horizontal, Isoelectric )Normal ST elevation – High take-off )V1-3 early repolarization Concave , After deep S, or with↑↑.T
The T wave
Vector – same direction as QRS complex .ex. Rt. Precordial leads always + in I, II, aVL, V3-6 always – in aVR -
The QT interval
Normal Value - QTc ≥ 0.40msec
QTc = QT/√RR
QTc calculation QT =0.64 RR
RR = 1.24 QT
√ RR = 1.114 QTc = QT/√ RR = 0.57
Normal E.C.G - summery
