interpretation made easy. lead placement limb leads must be placed on the limbs uses both positive...
TRANSCRIPT
Interpretation Made Easy
LEAD PLACEMENTLIMB LEADS MUST BE PLACED ON THE
LIMBSUses both positive and negative electrodesCurrent towards positive, view from negative
Precordial Leads
Acquisition & Transmission
Acquisition & TransmissionSkin Preparation
Helps obtain a strong signalSkin oils reduce adhesion of electrode
and hinder penetration of electrode gelDead, dried skin cells do not conduct
well
Acquisition & Transmission
Rubbing skin with a
gauzepad can
reduce skin oil
and remove some of
dead skin cells
Acquisition & TransmissionOther causes of artifact
Patient movement
Cable movement
Vehicle movement
Electromagnetic Interference (EMI)
Acquisition & TransmissionPatient Movement
Make patient as comfortable as possible Supine preferred
Look for subtle movement toe tapping, shivering
Look for muscle tension hand grasping rail, head raised to
“watch”
Acquisition & TransmissionCable Movement
Enough “slack” in cables to avoid tugging on the electrodes
Many cables have clip that can attach to patient’s clothes or bed sheet
Acquisition & TransmissionElectromagnetic Interference (EMI)
Can interfere with electronic equipment60 cycle interference is a type of EMILook for nearby cell phones, radios or
electrical devicesNo contact between cables & power
cordsTurn off or move away from AC devicesUse shielded cables; inspect for cracks
Limb Lead PlacementTraditional Placement
Acceptable Placement
Avoid placing on the trunk!!!
Chest Lead PlacementV1: fourth intercostal space
to right of sternumV2: fourth intercostal space
to left of sternumV3: directly between leads
V2 and V4V4: fifth intercostal space at
left midclavicular lineV5: level with V4 at left
anterior axillary lineV6: level with V5 at left
midaxillary line
Acquisition & TransmissionThings to look for
Little or no artifactSteady baseline
Acquisition & Transmission
12-Lead ValidationLead I – Global Negativity?
P, QRS and T Wave inverted?R Wave Progression?
R Wave size increases in V leadsTransition Zone?
R Wave should be predominately positive in V3 and V4
12-Lead ValidationLimb leadsP wave, QRS, and
T wave upside down in Lead I
Global negativityUpper limb leads
switched
12-Lead ValidationR wave
progressionR waves progress
in size from V1 to V4
If poor progression, check lead placement on electrodes
normal poor