Comprehensive Guide to Patient Identification and Normal ECG Interpretation

Hello everyone. I am Dr. Vinu, Assistant Professor  from the Department of Medicine. In this session,   we will be dealing with Patient Identification,  Preparation and Interpretation of a Normal ECG.   Before going into the session, I would like you to  know why do we request or why do we do an ECG for  

a patient. ECG is usually used in the evaluation  of symptoms like chest pain, palpitations,   breathlessness and syncope, because these symptoms  might be an indication of an acute cardiac event   like myocardial infarction, acute  heart failure and arrhythmias.

ECG is also used in the evaluation of electrolyte  imbalances like imbalances in sodium, potassium,   magnesium, calcium, etcetera. ECG is used during  the process of cardiopulmonary resuscitation and   also after the process of CPR. ECG is also used  in evaluation of side effects of drugs and toxins.  

Certain drugs like digitalis,  tricyclic antidepressants   are proarrhythmogenic and they can lead to certain  cardiac events, which can be identified in an ECG. Coming to the first step in an ECG recording,  

first is patient identification. Identifying  a correct patient is very, very important.   You should either identify the patient by using  the wrist bands which the patient wear; or, if   the patient is not able to communicate, at least  through the bystanders. The printed recording,  

that is the ECG paper should always bear the  correct identification details of the patient.   Coming to the next step of ECG  recording, is informed consent. This is one of the most important  step in the process of ECG recording.  

First thing, the patient should be given a clear  and precise information about the process of   this ECG recording. And also, the pe the  person who is performing the procedure should   introduce themselves and they should explain  about the process in a very short. And also,  

the person who is recording should also  inform the patient that the procedure is   going to be very brief, not more than 5  minutes and it is going to be painless. Also, information about the level of  undress and the use of adhesive electrodes  

should also be mentioned to the patient.  Coming to the third important step,   is positioning the patient. The patient should  ideally be positioned in a semi-recumbent position   with 45 degree inclination. If not  possible, a supine position is also enough.  

And you should make sure that the  limbs are well supported on the couch.   And also, you should make sure that the  patient is completely relaxed and comfortable. You should make sure that the limbs do not  touch the railings of the cot, because, either  

the limbs moving, moving around or the limbs  which are touching the railings can alter   your ECG recording. In patients whom the ECG  recording is altered, or because the patient is   not able to position properly because  of the pain, then you should mention  

or you should annotate in the ECG the  reason for suboptimal ECG quality.   Before recording an ECG, make sure  the patient is still and relaxed. This picture shows you the normal positioning of  a patient where the patient is completely relaxed,  

sitting in a semi-recumbent position with 45  degree inclination, with the recorder standing   to the right side of the patient, and an ECG  recording is made. Coming to the next step,   the equipment and clinical room specification.  

You should make sure that the room and the  equipment are clean. Next, the equipment   should be safe and it is ready to use with  correct date and time which is entered. Also, you should make a visual inspection  of the equipment, such as the cables,  

the wires, the plugs, and rule out any faults  in the machinery. For battery operated machine,   you should ensure that it is fully  charged before the procedure.   Coming to the next step, the environmental  conditions. This is also very critical step  

in an ECG recording process. The, you should  make sure that the room is safe, it is private,   either walled or screened or curtained. And  also, it should be quiet and comfortable. The room should be made or designed  in such a way that it is accessible  

for even the disabled patients. And also, the  couch should have height adjustable option   for, and also that should be accessible from  both the sides. And you should make sure that   it is stocked appropriately with adequate  batteries, electrodes, ECG papers, etcetera.  

And you should also have options for cleaning  and disposable of the waste materials properly.   Now, coming to the process of documenting. Either the digital documentation or  manual documentation is mandatory for  

all ECGs. The documentation should  have the following parameters.   One thing, first important thing is the patient's  name. Next is the patient's date of birth   or the age. Next is the patient's identification  number or the hospital number. The ECG should also  

have the data about the recorder and also  the person who has requested for an ECG.   Also, it should bear the date and time  along with name of the institution. And it should also have a mention about any  alterations in the standard lead positions.  

Coming to the next step of placing an electrode.  You all know that we have 4 limb electrodes and   6 chest electrodes. So, first coming to the limb  electrodes; you should remember in such a way that   each arm electrode has a separate colour code.  So, remember in the order of right arm, left arm,  

left leg and the right leg. The colours are  red, yellow, green and black respectively. These electrodes will have a specific colour  and the electrodes will also be named,   but remembering each arm electrode with that  particular colour is very, very important.  

This right arm limb lead is placed in the right  forearm proximal to the wrist. In this similar   way, the left arm limb lead is placed in the  left forearm proximal to the wrist. Coming   to the left leg limb lead, it is placed in  the left lower leg proximal to the ankle.  

Similar way, the right leg lead is placed in  the right lower leg proximal to the ankle. So, I think this picture will explain  you the colour code. So, this is the,   this is the limb electrode and this is the chest  electrode. The limb electrodes are marked as red,  

green, yellow and black. This is placed in  the corresponding arms to the corresponding,   with the corresponding colours. This picture,  the second picture is about the chest leads.   It is also coded with colours  red, yellow, green, brown, black  

and purple. It is named from C 1 to C 6.  So, V1; V1 to V6 has separate colours;   V1 is red; V2 is yellow; V3 is green; V4  is brown; V5 is black; and V6 is purple. These 6 leads are placed in the chest in  certain anatomical landmarks which is very,  

very important. So, for placing the chest  leads, you should first identify the   angle of Louis, that is your manubrium sterni.  This corresponds to your second intercostal space.   So, for placing V1, it is placed in the fourth  intercostal space at the right sternal border.  

V2 is placed similarly on the fourth  intercostal space on the left sternal border.   After placing V2, V4 should be placed. V4 is placed in the fifth intercostal  space in the mid-clavicular line. So,  

this is the mid-clavicular line.  V3 is placed between V2 and V4.   So, this picture will clearly tell you how V4 to  V6 is placed. V4, as you all know, it is placed in   the fifth intercostal space in the mid-clavicular  line and V5 is placed in the same horizontal  

plane, that is in the same first intercostal  space, but in the anterior axillary line. And   V6 is placed in the same horizontal plane  as V4, but in the mid-axillary line. Okay. So, now, you have been given a clearer idea  about placing the limb leads and the chest leads.  

Now, we will go to some special situations  where the positioning of the leads is not   possible as we have seen previously. One such  condition is, dextrocardia. Dextrocardia is a   condition which is the heart is placed on the  right side instead of the usual left side.  

So, the recording cannot be done in the usual  way. So, what we do is, we change the leads   and place them on the right side. How do we place? This picture will give you a clearer  understanding. We are not going to  

change the position of V1 and V2. It is in  the same position as before, but we change   this V3 to V6, exactly opposite as the left side.  We are not going to change any of the intercostal   spaces, any of the anatomical landmarks, but  exactly on the right side; like how we saw V3,  

V4, V5 and V6 earlier, but on the opposite  side. But, we name the leads as V1R to V6R. Now, coming to one another special situation,  is posterior wall myocardial infarction,   where your leads has to be placed at the back  of your chest. So, this picture will tell you  

how do we record a posterior wall recording. So,  we have leads V7, V8 and V9. These V7, V8 and V9   are placed in the same fifth intercostal  space, that is corresponding to V4,   but V7 is placed in the posterior axillary  line and V8 is placed in the tip of the scapula  

and V9 in the left paraspinal region. So, now  you know how do we record a posterior wall ECG. Okay. So, you have placed the leads  properly, but in certain conditions,   you may have certain abnormalities in the  ECG, not because of the cardiac activity,  

but because of some altered electrical  activity. So, for a good quality ECG,   you should make sure that it is devoid of these  abnormal electrical activities. One such thing   is the loose lead artefact. When you look at  this ECG, when you look at these uh waves,  

you might think there is something which is very  much abnormal with the heart; but it is not so. The scenario here is, these leads, that is,  2 and lead 1 are not attached properly in   their corresponding positions. This could be  either because of excessive sweat or it could  

be because the leads are not properly attached  because of less amount of adhesive material. So,   these are all the possibilities. To to avoid  this, you should make sure the skin is clear,   less hair and it is attached properly. So,  this is not some abnormal cardiac activity,  

this is an abnormal activity because of  the electrodes not being attached properly. Coming to this ECG, if you see this  point, this is the isoelectric line;   but this isoelectric line is somewhere  above this. Similarly, in this lead also,  

you have an isoelectric line, but isoelectric  line, instead of being here, it is somewhere here.   This is called as wandering baseline effect. This  could be because of uh movement of the patient   or abnormal respiratory moments, all those things.  So, this is also an artefact which can be avoided.

And now, coming to this ECG, when  you look at the first instant,   you may think it as atrial fibrillation, but when  you have a closer look at these leads, you can see   a P wave which is prior to a QRS. So, it is not  atrial fibrillation. This kind of abnormal moments  

is because of the muscle tremors, which  could be either because of uh anxiety   or it could be because of hyperthyroidism  related tremors or a Parkinsonian tremor,   shivering, etcetera. So, this  is also a kind of artefact.

And can you look at this point in the ECG where  you have very much abnormal activity? This is also   not a abnormal cardiac activity; this is also an  artefact because of electromagnetic interference;   that is, either because of having a mobile  phone or a television or a radio nearby. So,  

this should also be avoided. Okay. So,  now, what is a normal ECG? A normal ECG   should be as in this picture. It should have a  normal isoelectric line without any artefacts. The waveforms should be very much clearly visible.  So, this ECG has a regular rhythm. That is,  

the RR interval or regular of 84 beats per  minute. And the P wave morphology; that is,   the P wave morphology is an upright P waves  in leads 1 and 2. Okay. So, it is also normal.   It has a nominal QRS complex. So, the QRS  complex duration is less than 100 milliseconds,  

that is, not more than 4 small boxes. And the  P wave, each P wave is followed by QRS wave. You have a P wave here; you are a; you have a QRS  wave here. And the PR interval is also constant,   not more than 3 to 5 small boxes. So, a normal  ECG will have; this is called as sinus rhythm, a  

regular rhythm with a normal Q P P wave, a normal  QRS wave; that is, a P wave which is followed by   QRS, with a normal PR interval, with isoelectric  line remaining the same and without any artefacts.   So, before providing a final ECG  printout, you should make sure that  

the ECG is of good quality without any artefacts. The waveforms should be very much clearly visible.  And also, you should make sure that at the end of   the procedure, the electrodes are completely  removed and disposed of to the clinical waste.  

Thank you. I hope this session  was really useful to you.