RECORDING AN

ELECTROCARDIOG

RAM

Definition

Electrocardiograms a graphical

recording of electrical activity of

the heart detected by means of

surface electrodes measured by

using a galvanometer.

Purposes

To assess the cardiac function (rate , rhythm and

conduction).

To diagnose cardiac rhythm disorders(e.g. heart

block, dysrhythmias )

To diagnose cardiac diseases (e.g. myocardial

infraction).

To detect the effects of electrolyte imbalance on

cardiac function(e.g. hyperkalemia, hypokalemia,

etc).

To evaluate effects of treatment (e.g. administration

of cardiac drugs).

Article

ECG machine.

Electrodes for 12 lead ECG.

Electroconductive gel.

Front open gown or shirt for

patient .

Tissue paper.

Procedure:

Nursing action:

1.Explain the purpose of ECG and procedure to the patient reassure patient that procedure is painless and safe.

Rationale

Helps to gain patient’s co-operation

and reduces anxiety regarding procedure.

NURSING ACTION

2. ask female patient to remove all tight fitting

clothing around the chest. Assist patient to put on a

front open loose gown or shirt

RATIONAL:

Procedures requires placement of electrodes over

chest area.

3.Ensure that the ECG machine is in functioning

order.

4. ensure proper standardization of machine

a. set paper speed at 25 mm/ minute

b. provide standard 1 mV signal to ECG machine

so that the spike made will be 10 mm or 2 large

squares in height.

c. ensure that the machine is properly earthed.

rationale

Proper standardization of machine ensures a precise

recording of ECG

5.ask the patient to lie in supine position and be as

relaxed as possible.

If the patient needs to be transported to the ECG

department , transport him on a trolley. Never allow

him to walk till diagnosis is confirmed.

Rationale

Rigid posture and contraction of muscles may

result in artifacts on ECG record.

6.provide privacy by pulling the curtains around the

patient.

rationale

Procedure requires exposing chest area , which is

embarrassing for patient.

7.expose chest completely. Apply electrocunductive gel on lead placement sites and position all electrodes appropriately.

a. check for color codes of limbs and connect limb electrodes to all four extremities as per the manufacturer’s code.

b. place suction electrodes at appropriate sites (at figure)

v1-4th intercostals space on the right side, parasternal.

V2-4th intercostals space on the left side, parasternal.

V3-midway between v2 and v4

V4-5th intercostals space on side in the anterior axillary line.

V6-5th intercostals space on left side in the mid-axillary line.

c. ensure proper contact between the lead and skin.

shaving of the chest may be required in case of male

patients.

Rationale:

Proper contact between skin and electrodes and

proper placement of electrodes are very essential for

obtaining a good recording

8. instruct the patient that you are going to start the

recording and he/she should lie still in the bed

without moving till the recording is complete , which

may take 5-10 minutes.

Rationale:

Patient movement during recording causes artifacts

on ECG record.

9.record the ECG:

a. manual recording :

-record limb leads (I,II,III,AVR,AVL,AVF) by advancing

the medicine settings to the respective leads.

-to record chest leads (V1-V6), advance the suction

electrode to next position after recording each lead.

(ensure that machine is set for chest lead recording)

-recording long lead ll.

b. automatic recording:

place limb as well as chest electrodes in position and

ask for autorecording.

Wipe off the electroconductive gel from electrodes.

10.Check the ECG record for appropriateness and

presence of artificates, if any.

Rationale

In case of appropriate recording or presence of

artificates, recording needs to be repeated.

11.Inform patient that ECG recording is completed.

12. Remove electrodes from all limbs and chest

wipe off the electroconductive gel using tissue

papers. Assist patient in dressing.

13.Wipe off the electroconductive gel from electrodes

Rationale

After drying, the gel forms a crust over the electrodes

which may interfere with future recording

14.label the ECG:

a. write patient’s full name, inpatient/outpatient number,

date and time of recording.

b. record lead identification in case of manual record.

c. a standard lead should be labeled and pasted on ECG

card when manual record are obtained.

Rationale

Provide accurate identification data.

15. read and report ECG as follows:

a. rhythm

b. conduction intervals.

c. cardiac axis

d. a discription of the QRS complexes.

e. a description of the ST segments and T waves

Rationale

Helps to identify obvious gross abnormalities.

16. show ECG record to physician as soon as possible so what

further treatment orders can be obtained, if any.

The two types of ECG recordings are the 12-lead ECG and a

rhythm strip. Both types give valuable information about

Heart function. The six limb

leads—I, II, III, augmented vector right (aVR), augmented vector

left (aVL), and augmented vector foot (aVF)—provide

information.about the heart’s frontal (vertical) plane. Leads I, II,

and III require a negative and positive electrode for monitoring,

those leads bipolar. The augmented leads record information

from

one lead and are called unipolar.

The six precordial or V leads—V1, V2, V3, V4, V5, and V6—

provide

information about the heart’s horizontal plane.

The horizontal axis of the ECG strip represents time. Each

small block equals 0.04 second, and five small blocks form

a large

block, which equals 0.2 second. This time increment is

determined

by multiplying 0.04 second (for one small block) by 5, the

number

of small blocks that compose a large block

The ECG strip’s vertical axis measures amplitude in

millimeters

(mm) or electrical voltage in millivolts (mV). Each small

block represents 1 mm or 0.1 mV; each large block, 5 mm or

0.5

mV.

Elecplacement in 12 lead ECG electrode :

6 are chest electrodes

Called V1-6 or C1 -6

4 are limb electrodes:

.Right arm:red

.Left arm: yellow

.Left leg:green

.Right leg: black

How to work:

The 12-lead ECG records the heart’s electrical activity using a

series of electrodes placed on the patient’s extremities and

chest wall. The 12 leads include three bipolar limb leads (I, II,

and III),vthree unipolar augmented limb leads (aVR, aVL, and

aVF), and six unipolar precordial, or chest, leads (V1, V2, V3,

V4, V5, and V6). These leads provide 12 different views of the

heart’s electrical activity.

The limb leads and augmented limb leads

Leads I, II and III are called the limb leads. The

electrodes that form these signals are located on the

limbs—one on each arm and one on the left leg. The

limb leads form the points of what is known

as Einthoven's triangle.

Lead I is the voltage between the (positive) left arm

(LA) electrode and right arm (RA) electrode

Lead II is the voltage between the (positive) left leg

(LL) electrode and the right arm (RA) electrode

Lead III is the voltage between the (positive) left leg

(LL) electrode and the left arm (LA) electrode

Rate and rhythm

In a normal heart, the heart rate is the rate in which the sinoatrial

node depolarizes as it is the source of depolarization of the heart. Heart

rate, like other vital signs like blood pressure and respiratory rate,

change with age. In adults, a normal heart rate is between 60 and 100

beats per minute (normocardic) where in children it is higher. A heart rate

less than normal is called bradycardia (<60 in adults) and higher than

normal is tachycardia (>100 in adults). A complication of this is when the

atria and ventricles are not in synchrony and the "heart rate" must be

specified as atrial or ventricular (e.g., atrial rate in atrial fibrillation is 300–

600 bpm, whereas ventricular rate can be normal (60–100) or faster

(100–150)).

In normal resting hearts, the physiologic rhythm of the

heart is normal sinus rhythm (NSR). Normal sinus

rhythm produces the prototypical pattern of P wave,

QRS complex, and T wave. Generally, deviation from

normal sinus rhythm is considered a cardiac

arrhythmia. Thus, the first question in interpreting an

ECG is whether or not there is a sinus rhythm. A

criterion for sinus rhythm is that P waves and QRS

complexes appear 1-to-1, thus implying that the P

wave causes the QRS complex.

Once sinus rhythm, or not, is established the second

question is the rate. For a sinus rhythm this is either

the rate of P waves or QRS complexes since they are

1-to-1. If the rate is too fast then it is sinus

tachycardia and if it is too slow then it is sinus

bradycardia.

If it is not a sinus rhythm, then determining the rhythm

is necessary before proceeding with further

interpretation. Some arrhythmias with characteristic

findings:

Absent P waves with "irregularly irregular" QRS

complexes is the hallmark of atrial fibrillation

A "saw tooth" pattern with QRS complexes is the

hallmark of atrial flutter

Sine wave pattern is the hallmark of ventricular flutter

Absent P waves with wide QRS complexes with fast

rate is ventricular tachycardia

Normal rhythm produces four entities — a P wave, a

QRS complex, a T wave, and a U wave — that each

have a fairly unique pattern:

The P wave represents atrial depolarization.

The QRS complex represents ventricular

depolarization.

The T wave represents ventricular repolarization.

The U wave represents papillary muscle

repolarization.

SPECIAL CONSIDERATIONS

Note that the following can cause poor ECG

signal and or artificates on an ECG record.

Oily, dirty and scaly skin.

Dirty or encrusted electrodes.

Improper application of electrodes.

Loose or dislodged electrodes.

Patient’s movement.

Muscles tremor.

Broken cable wire.

Faulty grounding.

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