ELECTROCARDIOGRAPHY: January 2014

Tuesday, 28 January 2014

How to perform a good ECG .

PART 2-LEAD PLACEMENT

1.The first thing is get acquitted with lead placement.
2. Know the ECG machine and its controls.

Lead placement.
There are 12 leads during the recording of an ECG.
-6 chest leads- V1-V6
-6 Limb leads-.aVR, aVL, aVF, 1,2,3.

(3 limb leads are created by virtue of placing 3 limb leads- aVR, aVF, aVL and hence are known as imaginary leads.)

LIMB LEAD PLACEMENT.

-Let the patient lie supine on a couch, bed.
-Clean the electrode sites using some alcohol and cotton wool (swab)
-Put the limb electrodes on the inner aspect while having applied some gel to achieve good conductance.

USIPlace the limb leads appropriately.
They are color coded and marked for easy identification
The N -Neutral is the ground electrode placed on the right foot.

CHEST LEAD PLACEMENT

V1 -4th intercostal space on the right 1cm from the sternum

V2 -4th intercostal space on the left 1cm from the sternum.

V3 -Between V2 and V3

V4 -5th intercostal space mid-clavicular line.

V5 -5th intercostal space anterior axillary line.

V6 -5th intercostal space mid axillary line.

COMMON MISTAKE- is counting from the clavicle as your first rib.

Performance of a good ECG.

1. The ECG waves must be visible and clear.
The ECG waves such as the P ,QRS complex ,T waves must be visible on the ECG paper.
This makes it easier in identifying any pathological waveforms present.

2.Artifact free.
minimal or no artifact must be present.
Types of artifacts -
-Muscle artifacts obscure the identification of P waves.
-Respiratory artifacts as the patient breths in and out.
-Electrical artifacts from the mains.-Turn on the notch rejection filter at 50/60 Hz
-Baseline wander artifact caused by movement of the leads.
-Movement artifacts.- the patient ought to be still.

3.Patient data must be included.

In summary.

1.Prepare electrocardiography machine for use	-Check ECG machine is in good working order connect it to power.

2. Prepare client for ECG procedure	-Reassure the patient the procedure is safe and the reason for it. -Record client information -Review client medical history

3. Attach ECG electrodes	-Maintain the client's privacy and dignity throughout procedure -Complete preparation of client's skin for electrode placement as required -Position the client correctly and comfortably and place electrodes in accordance with client's needs and current standards -Attach leads correctly and double check lead placement

4. Produce an ECG tracing by printing

-Produce trace and check for interference, wandering baseline and amplitude

Make sure the waves are visible with no artifacts.

-Repeat trace if interference , increased amplitude or wandering baseline is identified

-Identify and action abnormal ECG patterns which require immediate medical attention

-Forward trace to cardiologist or requesting medical officer for reading

-Record test details according to department and organisation procedures



	5. Complete ECG procedure. -Remove ECG leads and electrodes from client -Refer the patient appropriately. -Clean ECG leads and electrodes on completion of procedure in accordance with infection control guidelines OR -Dispose of disposable ECG electrodes and other materials in accordance with waste management procedures. -Store ECG machine as required making sure there is no entanglement or kinks of the leads.This will increase the longevity of your machine as well as of electrodes.

Thursday, 16 January 2014

ORIGIN OF ECG WAVES- Conduction System of the Heart

ORIGIN OF ECG WAVES AND CONDUCTION SYSTEM OF THE HEART.
The (heart) cardiac muscle is able to :
1. Contract
2. Generate its own impulse/ electrical activity - automaticity
3. be excitable as the heart muscle responds to an appropriate amount of stimuli and generate an action potential---an electrical pulse that spreads across the entire heart.This knowledge is applied in (CPR) cardiopulmonary resuscitation.

4 Conduct or transfer the action potential from muscle cell to muscle cell originating at the sino-atrial (SA) node---the pacemaker of the heart.

An action potential from the SA node travels through the heart at a rate of 0.8 to 1 meter per second

The heart has primary and secondary sites for electrical generation.
1,The sino-atrial node.The primary source of the cardiac impulse or electrical power.
Located on the right atrium at the junction of the opening of the superior vena cava.
The others below are considered as secondary.
2.The atrioventricular node.
3. The Bundle of HIS
4.RIGHT AND LEFT BUNDLE branches
5.PURKINJE FIBERS
N/b The BACHMAN'S BUNDLE is responsible for the spread of the impulse to the left atrium for uniform atria contraction during systole.

The electrical impulse moves from the sino- atrial node via the AV node, bundle of HIS, bundle branches down to the purkinje system of fibers.
This is known as the conductivity system of the heart.
This important activity is responsible for the contraction of the heart and to initiate a heart beat.

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ECG WAVES.

FROM THE LAST POST WE IDENTIFIED THE ECG WAVES AND THEIR MEANING.

What is an ECG?
Electrocardiography as its known involves recording electrical potential originating from the heart. These potentials cause the heart muscle to contract and pump blood to the body via the aorta and to the lungs for oxygenation via the pulmonary artery.
These activities can be recorded on an ECG paper in form of waves.
These waves are as follows:
1.P wave represents atrial contraction.
2.QRS complex represents ventricular contraction.
3.T wave represents. ventricular relaxation
4.U wave though not common.- late ventricular relaxation

The identification of these waves is very important