HCA Workbook Recording an ECG
(Electrocardiograph)
.
Whanganui District Health Board 2010 With thanks to Counties Manakau District Health Board Workbook for Recording an Electrocardiograph 2
TABLE OF CONTENTS
Recording an ECG
1.0 Introduction Page 3
2.0 Learning Objectives Page 3
3.0 Direction Page 3
4.0 Content 1.0 The Electrocardiogram …………………………………….. 4 1.1 Indications for recording an ECG ………………………….. 4 1.2 Documentation on ECG ……………………………………. 5 1.3 Preparation for recording an ECG ………………………… 5 1.4 Lead placement …………………………………………….. 6
2.0 Troubleshooting when performing an ECG …………. 9 2.1 Baseline wander ……………………………………………. 10 2.2 Somatic Tremor ……………………………………………. 11 2.3 AC interference …………………………………………… 12 2.4 Other problems …………………………………………... 13
3.0 The waves of the ECG complex ………………………… 13
4.0 Important characteristics of the ECG ………………… 14 4.1 Sensitivity …………………………………………………. 13 4.2 Paper speed ……………………………………………... 14 4.3 Filters …………………………………………………….. . 15
5.0 Quiz to complete ………………………………………….. 16
5.0 Competency Assessment ……………………………………. 20
7.0 Checklist ………………………………………………………… 23
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 3
1.0 INTRODUCTION
The purpose of this work book is to enable the Nurse Assistant/ Health Care Assistant/ Patient Care Assistant (NA/HCA/PCA) to develop skills to take an accurate basic 12 lead ECG. When you have completed the workbook you will be required to complete 3 practical sessions with your Nurse Educator (at least one ECG on a female patient).
2.0 LEARNING OBJECTIVES At the completion of the ECG workbook you will be able to:
1. To define the reason why an ECG recording is useful 2. Explain and demonstrate the method used to record an ECG 3. Discuss and demonstrate the following factors relating to ECG technique - Patient approach - Electrode application - Identifying and correct artefacts - Care and maintenance of equipment 4. Discuss and identify the causes for interference and explain the steps that can be taken with the patient and surroundings to eliminate interference of the ECG tracing. 5. Discuss in detail the effect the filtering has on the recorded ECG 6. In relation with the Electrical Activity of the heart be able to identify the waves of the ECG complex. 7. Identify characteristics on the ECG recording 8. To demonstrate the ability to perform an ECG and complete the ECG quiz required for Competency assessment.
3.0 DIRECTION
Most Anatomy and Physiology books have a section on the heart and conduction system. Or the following resources may be helpful to complete this workbook Images:
Rib cage www.med.mun.ca/anatomyts/thorax.age.htm
Electrocardiograph Guidelines http://circ.ahajournals.org
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 4
4.0 CONTENT
1.0 The Electrocardiogram
An electrocardiograph (ECG) is a recording of the electrical activity of the heart
The electrical activity is generated within the heart and is conducted through the body tissues to the surface of the skin. The electrodes have a cream applied to them or gel inside them to help the conduction of the electrical signals from the patient’s skin to the ECG machine.
The electrodes are placed anywhere along the right arm, left arm, left leg and right leg and are connected by wires to the ECG machine. The chest electrodes are placed in specific sites over the heart by which are found by using land marks such as rib spaces.
The patient is required to lie still and relaxed for about 10 seconds while the recording is being taken. The ECG machine produces 12 different leads or views of the hearts electrical activity by comparing the signals from one electrode to other electrodes. The patients 12 Lead ECG is recorded onto graph paper to show the events with each beat during the time the recording was taken.
1. 1. Indication for recording ECG As a baseline ECG To record the serial progression of a myocardial infarction In the assessment of Chest Pain Changes in Heart Rate New irregular pulse Palpitations Dizziness Altered level of consciousness Syncope infarction To monitor effects of some medications
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 5
1.2 Documentation on ECG
Check that the ECG has documented on it:
1. Date 2. Time 3. Patient Label 4. Note if patient had chest pain at time of ECG 5. Note if there was any alteration to ECG machine e.g. Filter used, change voltages from 10mV to 0.5mV or any deviation from routine practice. 6. Ensure doctor that has requested ECG is notified that ECG is ready for review.
1.3 Preparation for recording an ECG Patient Education Explain the procedure to the patient. For example, reassure them that it is a quick and painless procedure that will take approximately 10 minutes and will record the electrical activity coming from their heart. Gain patient consent and ensure patient safety and privacy.
Environment Preparation The ECG machine should be placed on the patients’ left whenever possible. This will reduce the need to lean over the patient and will mean you can clearly see you have the correct positions for V4-V6.
The bed should be adjusted so that it is at a comfortable working height. Constant bending over could give you a sore back in years to come.
Patient Preparation The patient should be horizontal (lying flat) whenever possible. If a patient adopts different positions on different occasions when an ECG is being recorded, any ECG changes observed may be due to the change in position of the heart in relation to the electrodes instead of a change in the patient’s condition. The patient needs to be lying as still as possible to ensure a good reading. If it is not possible for the patient to lie horizontal then it needs to be noted on the ECG what position they were in at the time.
Skin Preparation The skin should be abraded by skin preps before attaching the electrodes. Shaving may be necessary if the chest hair is springy resulting in poor electrode contact. Fine hair may be parted.
If the skin is oily or the patient has been sweating alcohol wipes should be used and the skin dried before applying electrodes.
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 6 If the skin is not prepared properly then external interference is increased and if the patient moves, even breathes, baseline wander is more likely to occur.
The positioning of the electrodes needs to be precise. Variations in positioning should only be considered when correct positioning is impossible or in the cases of uncontrolled tremor (e. g. Parkinson’s disease).
1.4 Leads
Limb Leads The limb lead electrodes are placed anywhere along the right arm, left arm, left leg and right leg.
Chest leads
Finding the correct chest positions to place the electrodes is usually where most people have difficulty. The chest electrodes are placed in sites over the heart are found by using land marks such as rib spaces. The first landmark is the sternal notch at the top of the sternum in the middle of the chest. As you move your fingers down from the sternal notch you will feel the sternum change its angle. This is the Angle of Louis or sternal angle. From the angle of louis, moving your finger to the right you will find a space between the ribs. The rib space just below the Angle of Louis is the 2nd rib space, from here you can feel for the 3rd then the 4th rib space.
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 7
This 4th intercostal (gap between the ribs) space is where V1 and V2 are placed. It is important to make sure that the electrodes are positioned right next to (but not on top of) the sternum. Remember that rib cages are not perfect so that V1 and V2 will not necessarily be in line with each other – it is important to be aware of this especially in bypass patients where the sternum has been cut and sewn back together.
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 8 V1 (red) – Right sternal border of the fourth intercostal space (that is to the patients rights of the sternum) V2 (yellow) – Left sternal border of the forth intercostal space ( to the patients left of the stermum)
V3 (green) is on the mid point between V2 and V4
V4 (brown) is in the fifth intercostal space on the mid clavicular line
The mid-clavicular line needs to be found on the left-hand side of the patient. To do this you first need to find the medial end of the clavicle in the notch at the top of the sternum. Then feel for the lateral end of the clavicle in the shoulder. This is more difficult but you should feel a small dip as you hit the end of the clavicle.
A method to then get the mid-clavicular line is to place your thumb on the medial end of the clavicle and your little finger on the lateral (shoulder) end. Move your hand down the patient so that the middle finger moves parallel to the sternum – this is the mid-clavicular line. Stop in the region of the 5th intercostal space. Find the 5th intercostal space at the sternum and follow this space round to where it meets the mid-clavicular line.
V5 (black) is on the anterior axillary line at the level of V4
The anterior axillary line is parallel to the spine starting at the point where the left arm meets the torso. Move your finger along this line until it is horizontal with V4. This is the V5 position.
V6 (purple) is on the mid axillary line at the level of V4
The mid-axillary line is between the anterior and the posterior axillary line. To find the posterior axillary line (also where V7 would go) feel where the axilla ends and move your finger down this line parallel to the spine. Stop when you reach the point horizontal with V4 and V5. This is the V6 position.
Other things to note:
If a patient has an amputated right leg, both electrodes can be placed on the left leg, (this does not work with any other limb lead).
If you are recording a paediatric ECG, V3R is required
If the patient has dextrocardia (heart is on the right rather than the left) then a special ECG may be requested wherein the chest electrodes need to be positioned in mirror image.
This means that V1R is in V2 position and V2R is in V1 position. V3R-V6R is positioned as normal but on the right side of the body.
If you have recorded an ECG in a sitting position as opposed to supine this should be marked on the tracing as it may change the recording slightly affecting its reproducibility.
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 9 If you have tried to eliminate artefact but have been unsuccessful it is important that you note this on the ECG so that the doctors know that it was the best tracing you were able to get.
2. 0 Trouble shooting when performing an ECG
When looking at the recording and there is interference, look at which leads are causing the problem as indicated below. When looking at the recording if there is any: Interference in the tracing that is from leads II, III and AVF = left leg tension/moving Interference in leads I, II and AVR = right arm tension/ moving Interference in leads I, III and AVL = left arm tension/moving
There are 3 types of interference you can get when performing an ECG: Baseline wander Somatic tremor AC interference We will look at each of these problems and how to solve them:
2.1 Baseline wander.
The baseline of the ECG moves up and down instead of moving in a steady line.
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 10 Caused by: - Poor skin preparation - Loose electrodes - Broken leads - Drag or movement of the leads - Respiratory swing To correct: - Ask the patient to stay still and ensure that the cable is resting on the bed, not swinging loosely. - If the patient is short of breath they may need to sit up slightly to help them breathe easier - Make sure electrodes are firmly attached - Re-prep the skin using alcohol wipes if patients skin is sweaty or oily It is important to remove any baseline sway as it will make it difficult, if not impossible, for the doctor to interpret the ECG (in particular the line between the S wave and T wave). Any changes in this segment of the ECG can indicate serious cardiac problems including myocardial infarction/ heart attack (no blood to parts of the heart muscle) or ischemia (the heart not getting enough blood).
2.2 Somatic tremor.
Muscle tremor giving and irregular ‘spiky’ baseline. Caused by: - Patient feeling tense - Patient having uncontrolled tremor
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 11 - Cold patient
To correct: - Reassure patient and ask them to relax with particular focus on shoulders, arms and legs. - If cold supply blanket to warm them up. - If patient is unable to relax or has an uncontrolled tremor then the limb electrodes may need to be moved closer to the trunk of the body ( ie further up arm or leg) where the tremor will be less marked
It is important to remove any somatic tremor as it can interfere with the interpretation of the ECG by hiding the different waves of the ECG complex. It is important to see each wave as clearly as possible as even subtle changes in the ECG can be important in diagnosing and treating a patient.
2.3 AC interference.
Electrical mains supply interference at a 50Hz frequency that gives a regular sine wave oscillation of the baseline
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 12
Caused by: - Electrical equipment not being earthed properly - Patient touching something metal - Faulty right leg connection - Wiring in walls and surrounding electrical equipment To correct: - Touch patient as you touch ECG machine - Disconnect any non essential electrical equipment (check with ward staff before disconnecting medical equipment) or move them away from the patient - Avoid large loops in the ECG leads (loops can act to pick up interference especially in electrically noisy environments) and try and keep together - Position leads at right angles across the body - Check and change leads if faulty or broken
It is important to remove any AC interference for the same reasons as somatic tremor. AC interference prevents the ECG from being properly interpreted and needs to be eliminated.
2.4 Other problems
Failure of the machine to switch on
- Ensure all power switches are on.
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 13 - Battery pack may need to be recharged
- Failure of the screen to come on - Check brightness/contrast dial on side of the screen/machine.
- All leads have straight line - Check if patient breathing and has a pulse, if not call an emergency. - Check ground lead (right lead) - Check lead connection at the back of the machine
- Certain leads have a straight line - Check that the lead is connected to its electrode - Check the electrode on the patient – if loose then reapply - If on going problem with same lead then it may be broken
If problems can not be fixed by this list then report problem to Registered Nurse.
3.0 The ECG complex The ECG complex consists of - the P wave - the QRS complex - the T wave
Each of these reflects the electrical activity of the heart during different times of the cardiac cycle. The P-QRS-T waves are repeated each time the heart beats. The P wave shows us the electrical activity of the heart when the atria are contracting The QRS complex shows us the electrical activity of the heart when the ventricles are contracting The T wave shows us the electrical activity of the heart when the ventricles are relaxing Note: no electrical activity is seen on the ECG when the atria are relaxed. It is important to make sure all these complexes are clearly seen on an ECG and this is done by making sure the ECG is free from artefact. Some times these waves won’t all be present but if the ECG is clear and artefacts free, this will be because the patients heart has an abnormal rhythm.
By examining the pattern of the waves and the time interval between the cycles and parts of the cycles, the physician can obtain valuable information about the state of the heart and its conduction system.
The 5 waves of the ECG complex
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 14 T P
QRS
4.0 Important characteristics of the ECG
Sensitivity This is a measure of the amount of voltage picked up from the heart. This can be checked but looking at the calibrations printed with each ECG using the standard of 1mV (10 small squares on the ECG paper). The calibration markers appear at the start of the line and appear rectangular in shape.
The ECG machine will print out each ECG at the standard setting of 10mm/mV (1mV of electricity) from the heart which will be shown as a 10 small square deflection on the ECG so the standard sensitivity setting is 10mm/mV
If the complexes are large the machine will ask if you want to print the ECG at a sensitivity of
5mm/mV, which will make the complexes look smaller. The other sensitivity is 20mm/mV which will make the complexes look larger.
Any changes made from the standard 10mm/mV must be clearly marked on the ECG so the clinician is not mislead.
Paper speed There is a standard paper speed on all ECG machines to ensure continuity. This is essential for the clinicians as the intervals on the PQRST tracing can be measured to give important information about the heart e.g. heart rate.
The standard paper speed is 25mm/second.
The alternative to this is 50mm/second which is used only when asked for by the doctor. Usually this is used when a patient has a fast heart rate and the ECG is difficult to interpret.
Filters
A filter is a device that is used to minimise artefact on the ECG recording. If you think of a coffee filter it separates the beans from the water. In ECG terms the filter takes away the artefacts we do
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 15 not need. However the filter should only be used as a last resort. Bear in mind that when the filter removes the artefact it also takes away slight definition from the ECG.
5.0 Review Quiz
1. When would you explain the procedure of recording an ECG to the patient? Only if they hadn’t had an ECG done before Never – they wouldn’t understand anyway Every time – it is a basic patient right to have every procedure performed on them explained.
2. When performing an ECG if possible you should always be on the patients left. Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 16 . True or False?
3. What is the best position for the patient to be in when performing an ECG. Sitting up Standing Lying as flat as is comfortable
4. Draw a line matching the chest positions with their lead number.
Mid point between V2 and V4 V3
Mid axillary line at the level of V4 V6
Right sternal border of the forth intercostal space V1
Anterior axillary line at the level of V4 V5
The fifth intercostal space on the mid clavicular line V4
Left sternal border of the fourth intercostal space V2
Review of ECG troubleshooting 5. With baseline wander what would you see on the ECG: an irregular spiky baseline a baseline that moves up and down a baseline that shows a regular sine wave oscillation
6. What causes AC interference a tense patient poor electrode contact nearby electrical equipment
7. how would you try to remove somatic tremor artefact from the ECG reassure patient and ask them to relax make sure they were warm move electrodes higher up body if tremor uncontrollable Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 17 all of the above
Draw the following 8. Baseline wander Refer to the ECG pg 9
9. Somatic tremor Refer to the ECG pg 10
10. AC interference Refer to ECG pg 11
11. If there is artefact present on ECG, despite trying your best to remove it, you should make a note of this on the ECG leave the ECG in as it is tell the doctors that the ECG can not be done on this patient due to artefact
12. Why is it important that each wave of the ECG complex is seen clearly?
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 18 .
Review on characteristics of the cardiograph
13. What is the standard sensitivity setting a) 5mm/mV b) 10mm/mV c) 20mm/mV
14. What is the standard paper speed a) 25mm/second b) 50mm/second c) 75mm/second
15. True or False. The filter should be turned on at all times as it is a quick way to remove any artefact T / F on the ECG.
Obtaining an accurate ECG
Correct limb and chest lead placement is vital to ensure the accuracy of the ECG.
16. Describe how you would use the anatomical landmarks to help you find correct positions for the electrode placement
LA
RA
LL
RL
V1 V2
V3
V4
V5
V6
17. How many electrodes are used in a 12 lead ECG?
18. How many Leads are recorded on an ECG?
19. List five indications where an ECG is used as a diagnostic tool
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 19 20. How can you prevent cross infection when obtaining an ECG?
.
21. Mr Collins is a fit 65 year old being admitted for an Inguinal Hernia Repair. The anaesthetist has requested a routine ECG. Write a paragraph explaining to Mr Collins the reason for the ECG and what it will involve..
______
6.0 COMPETENCY ASSESSMENT
Recording a 12 lead Electrocardiogram Competency: The candidate demonstrates accurate recording of the ECG
Name: Area/Ward Achieved Knowledge :Identifies the key features of the ECG Machine Describes main indications for recording an ECG Practice Preparation of patient and Environment Identifies patient as per hospital policy Explanation of the procedure
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 20 Preparation of patient: positioning, and privacy Recognises and removes where possible potential sources of electrical interference Preparation of equipment Ensures ECG machine is unplugged from mains electricity Checks electrodes Checks supply of ECG electrode tabs Ensures the ECG machine settings are correct Paper speed Frequency Date Time Appropriate format is selected Recording ECG Locates landmarks for chest lead position accurately Selects appropriate positions for limb leads Places tab electrodes on prepared sites Connects leads to tab electrode Takes a recording Ensures baseline is artefact free Troubleshoot and identifies any artefacts Scans ECG for presences of serious arrhythmias States rationale for performing right sided chest leads Identifies the location of right sided leads V3r,V4r Removes tab electrodes Ensures patient is comfortable before leaving
Evaluation – Competency Assessment Complete Competency assessment as above with preceptor or RN Feedback______
Assessors Signature: ______Designation: ______Date: ______
Recording a 12 lead Electrocardiogram Competency: The candidate demonstrates accurate recording of the ECG
Name: Area/Ward Achieved Knowledge :Identifies the key features of the ECG Machine Describes main indications for recording an ECG Practice Preparation of patient and Environment Identifies patient as per hospital policy Explanation of the procedure Preparation of patient: positioning, and privacy Recognises and removes where possible potential sources of electrical Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 21 interference Preparation of equipment Ensures ECG machine is unplugged from mains electricity Checks electrodes Checks supply of ECG electrode tabs Ensures the ECG machine settings are correct Paper speed Frequency Date Time Appropriate format is selected Recording ECG Locates landmarks for chest lead position accurately Selects appropriate positions for limb leads Places tab electrodes on prepared sites Connects leads to tab electrode Takes a recording Ensures baseline is artefact free Troubleshoot and identifies any artefacts Scans ECG for presences of serious arrhythmias States rationale for performing right sided chest leads Identifies the location of right sided leads V3r,V4r Removes tab electrodes Ensures patient is comfortable before leaving
Evaluation – Competency Assessment Complete Competency assessment as above with preceptor or RN Feedback______
Assessors Signature: ______Designation: ______Date: ______
Recording a 12 lead Electrocardiogram Competency: The candidate demonstrates accurate recording of the ECG
Name: Area/Ward Achieved Knowledge :Identifies the key features of the ECG Machine Describes main indications for recording an ECG Practice Preparation of patient and Environment Identifies patient as per hospital policy Explanation of the procedure Preparation of patient: positioning, and privacy Recognises and removes where possible potential sources of electrical interference Preparation of equipment
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 22 Ensures ECG machine is unplugged from mains electricity Checks electrodes Checks supply of ECG electrode tabs Ensures the ECG machine settings are correct Paper speed Frequency Date Time Appropriate format is selected Recording ECG Locates landmarks for chest lead position accurately Selects appropriate positions for limb leads Places tab electrodes on prepared sites Connects leads to tab electrode Takes a recording Ensures baseline is artefact free Troubleshoot and identifies any artefacts Scans ECG for presences of serious arrhythmias States rationale for performing right sided chest leads Identifies the location of right sided leads V3r,V4r Removes tab electrodes Ensures patient is comfortable before leaving
Evaluation – Competency Assessment Complete Competency assessment as above with preceptor or RN Feedback______
Assessors Signature: ______Designation: ______Date: ______
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010 Workbook for Recording an Electrocardiograph 23
7.0 CHECKLIST
Workbook completed
Quiz completed
Three ECG’s completed and signed
Workbook handed in to the Nurse Educator.
Version: 1 Last Updated: 2010 Next Review Date: 2013 Date First Issued: July 2010