1. Resting ECG
An overview

2. Electrocardiogram (ECG)
Graphic recording of the electrical activity (impulses) generated by the heart
Placement of electrodes on the body will allow for detection of these impulses

3. ECG
Generally standard procedure to monitor and record the ECG during a graded exercise test (GXT)

4. ECG
Equipment
adhesive silver-silver chloride electrodes with electrolyte gel or paste
electrical wires
amplifier
monitor
recording apparatus
computer to program the treadmill

5. Twelve views of the heart
Lead - two or more electrodes placed on the body in designated anatomical locations
1. Standard Limb Leads (3)
2. Augmented Limb Leads (3)
3. Chest Leads (6)
Use 10 electrodes

6. Anatomical Locations of Leads
Right Arm (RA) - right shoulder below the clavicle but above the border of pectoralis
Left Arm (LA) - left shoulder below the clavicle but above the border of pectoralis (in deltoid fossa)

7. Anatomical Locations
Right Leg (RL) - halfway between the costal margin (ribs) and the iliac crest (hip bone)
Left Leg (LL) - halfway between the costal margin and the iliac crest

8. Anatomical Locations V1 – right of sternum V2 – left of sternum
V3 - midway between positions for V2 and V4
V4 - left midclavicular line

9. Anatomical Locations
V5 - Horizontal level of V4 at left anterior axillary line
V6 – horizontal level of V4 at left midaxillary line

10. Standard Limb Leads Lead 1 - *Left Arm (LA) - Right Arm (RA) angle 0
Lead 2 - *Left Leg (LL) - Right Arm (RA) angle 60
Lead 3 - *Left Leg (LL) - Left Arm (LA) angle 120
* indicates positive electrode

11. Augmented Limb Leads
Augmented – need to amplify the voltage to get a tracing of the same magnitude as Leads 1,2,3

12. Augmented aVR - Augmented Voltage Right Arm
*RA and (LA-LL) angle -150
aVL - Augmented Voltage Left Arm
*LA and (RA-LL) angle -30
aVF - Augmented Voltage Left Foot
*LL and (RA-LA) angle +90

13. Leads II, III, and AVF - inferior lead I and AVL - left lateral leads
view of inferior surface of heart
I and AVL - left lateral leads
view of left lateral wall of heart
AVR - loner

14. Structures of the Heart
SA Node
Atria
AV Node
Common Bundle
Right and Left Bundle Branches
Purkinje fibers
Ventricles

15. Electrical Events 1. Sinus Node in the atrium
2. Depolarization left, inferior, and anterior through right atrium
3. Spreads through left atrium
4. AV node and Bundle of His
5. Left and Right Bundle Branches

16. Electrical Events
6. Impulse crosses the intraventricular septum from left to right
7. Depolarization of ventricles simultaneously

17. ECG Waverforms P - atrial depolarization
PR interval - an interval encompasses at least one wave plus the connecting line
time from start of P wave to beginning of QRS
time for depolarization of the atria to beginning of ventricular depolarization

18. Waves QRS - ventricular depolarization first deflection down is Q
first deflection up is R
first downward deflection following an upward deflection is S

19. Waves ST segment - a straight line connecting two waves
ventricular isoelectric period
time from end of ventricular depolarization to the start of ventricular repolarization
T wave - ventricular repolarization

20. Depolarization
Positive deflection - a wave of depolarization moving toward a positive electrode
Negative deflection - a wave of depolarization moving away from a positive electrode
biphasic - wave moving perpendicularly to the positive electrode (positive deflection precedes negative)

21. Repolarization
Positive deflection - a wave of repolarization moving away from a positive electrode
Negative deflection - a wave of repolarization moving toward a positive electrode
biphasic - wave moving perpendicularly to the positive electrode (negative deflection precedes positive)

22. PHASES OF THE RESTING ECG

23. Leads and the P wave
Atrial Depol wave moving toward leads I, AVL, II, and AVF  positive deflection
Lead III biphasic
Lead AVR  negative deflection

24. Normal ECG Responses to Exercise
Minor and significant changes in P-wave
Superimposition of the P and T waves of successive beats
Increases in Q wave amplitude
Slight decreases in R wave amplitude
Increases in T wave amplitude

25. Normal Responses Minimal shortening of the QRS duration
Depression of the J point
Rate-related shortening of the QT interval

26. Time and Voltage Duration - seconds Amplitude - millivolts
Configuration - shape and appearance

27. EKG Paper Light Lines (small squares)- 1mm x 1mm
Dark Lines (large squares) - 5mm x 5mm
Small square s and/or .1 mV
Large Square - .2 s and/or .5 mV