understanding the role of ecg in tip placement€¦ · 11 p-wave changes on intravascular ecg lead...

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Understanding the Role of ECG in Tip Placement ARROW® VPS G4™ Device

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Clinician will be able to:

• Describe the five waveforms of the heart’s electrical activity

• Understand correlation between waveform activity and the

ARROW® VPS G4™ Device

Objectives

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• An electrocardiogram (ECG) is a diagnostic test that measures and

records the electrical activity of the heart

• It translates the heart’s electrical activity into line tracings on paper

Principles of ECG: Waveforms

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• A complete cardiac cycle has five identifiable waveforms

• These electrical impulse patterns are labeled P, Q, R, S, and T waves

• Each of these five waveform segments represents electrical activity

within a specific area of the heart


P

Q

R

S

T

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• The first half of the P-wave appears when the SA node activates the

right atrium and reaches the AV node

• When the P-wave is complete, the left atrium and the AV node are

completely activated

• The line after the P-wave indicates the activation of the AV junction

• A normal P-wave indicates both atrial chambers have contracted and

begun to empty blood into the ventricles

• In a normal heart rhythm, the P-wave is rounded and positive or above

the baseline


P-wave corresponds

to contraction of atria

P

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• The negative Q-wave indicates the ventricular septum has been

activated

• The QRS complex indicates the ventricles have been activated from

the inside to the outside of the surface. Depolarization has begun

• QRS Complex = ventricle contraction


QRS corresponds to

ventricles contracting

Q

S

R

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• The ST segment indicates the end of depolarization and the beginning

of ventricular repolarization

• The ventricles are returning to an electrically ready state to receive

next impulse


S

T

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• The T-wave represents ventricular repolarization

• The ventricles are preparing to receive the next electrical impulse

• A normal T-wave is rounded


T-wave

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9

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Electrophysiology

Normal Sinus

Rhythm

Atrial Fibrillation

Conduction

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P-wave Changes on Intravascular ECG Lead

External ECG

Same patient intravascular

lead II

33.5 34 34.5 35 35.5 36 36.5 37

1900

2000

2100

2200

2300

38 38.5 39 39.5 40 40.5 41 41.5 421600

1800

2000

2200

2400

2600

2800

10.5 11 11.5 12 12.5 13 13.5 14

1600

1800

2000

2200

2400

2600

2800

205.5 206 206.5 207 207.5 208 208.5 209 209.51500

2000

2500

In CAJ

In right atrium

P-WAVE Patients

RA

CAJ

SVC

Atrial P-wave grows

with increasing

proximity to the RA4

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P-wave Accuracy Range Greater Than Optimal

Normal P-wave

range

33.5 34 34.5 35 35.5 36 36.5 37

1900

2000

2100

2200

2300

10.5 11 11.5 12 12.5 13 13.5 14

1600

1800

2000

2200

2400

2600

2800

205.5 206 206.5 207 207.5 208 208.5 209 209.51500

2000

2500

Maximal P-wave

range

Biphasic P-wave

range

RA

CAJ

SVC

SVC

2-5 cm

RA

0-3 cm

RA

2-5 cm

Landing

zone lower

1/3 of SVC-

CAJ

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50%

3 cm

3 cm

3 cm

P-wave Inconsistency

Jeon et al, CAN J ANESTH 2006 / 53: 10 / pp 978–983

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• Identification of P-waves is essential to understanding CVC placement

using the ECG method

• Inserter must be able to recognize P-wave changes on the ECG

monitor

• When inserting a central venous catheter, as the tip enters the SVC

and heads toward the right atrium, the height of the P-wave changes

• Identifying changes in the P-wave, as the catheter is inserted, allows

accurate identification of tip position when entering the SVC or Right

Atrium

ECG Principles

understanding the role of ecg in tip placement€¦ · 11 p-wave changes on intravascular ecg lead...

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