EKG, Ch 3, Lead Morphology and Placement

Bipolar leads

Leads that require a positive pole and a negative pole

electrocardiography

Recording of the heart's electrical impulses,

electrodes

adhesive patches attached to the skin to receive electrical signals from the heart. The gel on the pad conducts electrical impulse.

Which limbs does Lead I involve

Measures the current traveling between the R and L arm. R arm -, L arm +

Which limbs does Lead II involve

measures the current traveling between the right arm and the left leg. R arm -, L leg +

Which limbs does Lead III involve

Measures the current traveling between the left arm and the left leg. L arm - and L leg +

triaxial diagram

the diagram of leads I, II, III joined at the center of aVR, aVL, and aVF joined at the center

Einthoven's Triangle

the triangle formed by joining leads I, II, III at the ends

frontal leads

limb leads I, II, III, aVR, aVL, and aVF, joined at the center (hexiaxial diagram)

Einthoven's Law

lead I + lead III = lead II

Which limb does aVR involve?

measures the current traveling toward the right arm. Positive electrode. Electrode on R arm.

Which limb does aVL involve?

measures current traveling toward the left arm. Positive elctrode. Electrode on L arm.

Which limb does aVF involve?

measures current traveling toward the L foot or leg. Positive electrode. Electrode on L leg.

Augmented leads

Generation of small waveforms on the EKG paper that the machine must augment the size of so it will appear on the EKG.

unipolar

require only one electrode to make the leads.

hexiaxial diagram

used to help determine the direction of current flow in the heart

precordial leads

chest leads that see a wraparound view of the heart from the horizontal plane, named V1, V2, V3, V4, V5, and V6.

Describe placement of precordial lead V1

fourth intercostal space, right sternal border (abbr. 4th ICS RSB)

Describe placement of precordial lead V2

fourth intercostal space, left sternal border (4th ICS, LSB)

Describe placement of precordial lead V3

halfway between V2 and V4

Describe placement of precordial lead V4

fifth intercostal space, midclavicular line, (5th ICS, MCL)

Describe placement of precordial lead V5

fifth intercostal space, anterior axillary line (5th ICS, AAL)

Describe placement of precordial lead V6

fifth intercostal space, midaxillary line (5th ICS, MAL)

intercostal spaces

spaces between the ribs

midclavicular line

line down from the middle of the clavicle

anterior axillary line

line down from the front of the axilla

midaxillary line

down from the middle of the axilla

telemetry

method of monitoring a patient's rhythm continuously and remotely. The patient carries a small transmitter that relays his or her cardiac rhythm to the receiver located at another location.

What direction is an electrical impulse traveling if it graphs a positive complex on the paper

impulse is traveling toward or parallel to a positive electrode...

What direction is an electrical impulse traveling if it graphs a negative complex

impulse is traveling away from a positive electrode...

What direction is an electrical impulse traveling if it graphs an isoelectric complex

impulse is traveling perpendicularly to the positive electrode...

What direction is an electrical impulse traveling if it graphs no complex at all

No direction. Nothing is written on the paper because no impulse at all is detected

Describe the direction of normal deflection for the Bipolar leads:
Lead I
Lead II
Lead III

Normal QRS deflections should be positive for all of the bipolar leads

Describe the direction of normal deflection for the Augmented leads:
aVR
aVL
aVF

aVR -negative
aVL - positive
aVF - positive

vector

arrow that points out the general direction of the current flow

Describe the direction of normal deflection for the Precordial leads:
V1
V2
V3
V4
V5
V6

Normal QRS deflections
V1 - negative
V2 - negative
V3 - half up/half down Or Biphasic
V4 - half up/half down Or Biphasic
V5 - positive
V6 - positive

V4, V5, V6

normal QRS deflections - half up/down, positive, positive

Upright (except aVR)

In the frontal leads, all QRS complexes should be...

Negative

In precordial leads, V1 and V2's QRS' should be...

Isoelectric

In the precordial leads, V3 and/or V4 QRS' should be...

Positive

In the precordial leads, V5 and V6 QRS' should be...

List the Bipolar Leads

Leads I, II, & III

List the Augmented Leads

aVR, aVF, aVL

List the precordial leads

V1, V2, V3, V4, V5, V6

Eithoven's Law

Lead I + Lead III = Lead II
(The height of the QRS of Lead I + the height of the QRS of Lead III should equal the height of the QRS of Lead II)
If this is the case, your lead placement is correct.

Lead

A "view" of the heart. Or electrocardiographic picture of the heart.

How many electrodes are placed on the body for a 12-Lead EKG?

10 Electrodes

What is the purpose of the electrode/wire placed on the R leg?

It is the grounding wire. It is green in color.
It is not involved in any "views" of the heart.

Where is the ground wire placed?

R leg.

Limb Leads

Another term used for the bipolar and augmented leads because the electrodes are placed on the limbs (arms & legs). Also called Frontal Leads.

Standard Leads

Another term for Bipolar Leads. Also called Frontal Leads
Leads I, II & III

Frontal leads

Another term for bipolar. and augmented leads because they look at the heart from the front of the body only

3 - Lead Monitor

3 Electrodes placed on the chest.
White placed subclavicular, R side of chest.
Black placed on Subclavicular L side of chest
Red placed on L side of abdomen
"White on Right. Smoke over Fire"
This type is used for continuous monitoring/telemetry

Biphasic

QRS deflection is half up and half down (half positive and half negative)

What would you graphed on the paper if there is no electrical impulse detected?

A flat line

ICS

Intercostal Space

RSB

Right Sternal Border

LSB

Left Sternal Border

MCL

Midclavicular Line

AAL

Anterior Axillary Line

MAL

Midaxillary Line

5 - Lead Monitor (Holter Monitor)

Typical Holter Monitor setup. The most common lead placement is as follows:
White - Right subclavicle, Right of Sternum
Black - Left subclavicle, Left of Sternum
Red - Left lower chest
Green - Ground lead; Right lower Chest
Brown - Just below and to the R