Step-by-Step Guide to Recording a Standard ECG Accurately

Good morning. I am Dr. A. Ahamed  Basha, Professor of Physiology,   Chettinad Hospital and Research Institute. Today,  I will be speaking about how to record a standard   ECG that is recording of a standard ECG. ECG, an important diagnostic tool in cardiac  

care. Modern ECG machines are portable, and they  are very much user friendly. But even though if   it is an user friendly device, errors in recording  an ECG may end up with wrong diagnosis and also it   will affect the management of cardiac diseases. So  the greatest challenge in recording of an ECG is a  

consistent recording technique must be adopted. The personnel, whoever recording ECG needs to be   qualified, trained, and he or she has to  be an expertise in the recording technique.   So in this module, we are going to see a clear  step-by-step approach in recording of an ECG.  

In ECG - OSCE guide, we are going  to see a step-by-step approach under   following heading. Number one is what are the  prerequisites. In prerequisites, ECG recording   personnel, that is we are going to see who can  record the ECG and how to identify the patient  

and how to maintain the privacy of the  patient. Next is patient preparation.   Under patient preparation, we are going to  learn about how to get an informed consent,   how to place the patient over the couch.  

Next, how to prepare the skin for the  placement of electrode we are going to learn.   Under electrode placement, we are going to learn  about how to place the limb leads and where to   place the limb leads as well as chest leads. That  is the techniques for locating the chest leads.  

Next, how to obtain a good quality ECG  recording. In that we are going to see   what is the paper speed to be kept while  recording. How to calibrate the ECG mission   and how to avoid the artefact. After  recording ECG what are the steps to be done  

we are going to see one by one. First we are going to see ECG recording personnel.   ECG recording has to be done only in the health  care setup. The ECG recording personnel must be a   qualified, trained and expertise in the recording  techniques. The personnel may be a doctor, a nurse  

or an ECG technician or a researcher  especially those who are involving in   the ECG related research activities  and allied health professional.   So these health care providers can  record ECG with proper training and  

expertise in the recording techniques. Next patient identity. The healthcare provider   must confirm the patient identity before recording  the ECG. How to confirm the patient identity?   Patient identity can be confirmed by checking OPD  or IPD number. Next, the healthcare provider has  

to check the name with initial because sometimes  two person maybe with the same name. Hence,   always check the name with initial. Next healthcare provider has to check   for age of the patient, sex of the patient,  then wristband, especially for the pediatric  

population wristband has to be checked for  the confirmation of the patient identity.   Further, the healthcare provider can check for  case record to confirm the patient identity.   But in case if the patient is not able  to speak or not in a good orientation,  

the healthcare provider can ask the caretaker of  the patient to confirm the patient identity.   Patient privacy. The healthcare provider  must maintain the health information privacy.   And also he or she has to adopt the  human values, especially at the time of  

recording an ECG. The ECG recording to be done in  a closed room. If the patient is a female patient,   one of the female ward staff member or a  patient attender must be present throughout the   ECG recording procedure. Next, is informed consent. The healthcare provider  

must inform the patient about the procedure of  ECG recording in a friendly language. That is,   the healthcare provider has to say to the patient  that ECG is a record of an electrical activity   and the procedure involves placing  of an electrode over the body sites  

and that electrode is connected to the ECG  machine. The ECG machine records the ECG.   So entire procedure has to be explained to the  patient and gain a consent from the patient to   proceed with the ECG recording. Next, we are going to see  

patient position. Under patient position, exposure  of lower limb and wrist is necessary to connect   limb leads. Adequately expose the patient  chest for placement of precordial electrodes.   Offer a blanket to the patient so that patient has  to cover the entire precordial area. Only at the  

time of recording the for placement of electrode  that particular area alone has to be exposed.   The patient has to lie down on a clinical  examination couch with the head tilted   at an angle of 45 degree. Ask the patient  whether the patient is feeling any discomfort  

or any breathlessness, pain etc.  Only if the patient is comfortable   then you proceed for ECG recording. Next we are going to see skin preparation.   Skin preparation is done in order to avoid  an artefact in ECG. Some people may have  

additional hair in their body. That additional  hair may interfere ECG recording. In order to   avoid that, wherever you are going to place the  electrode, that particular area alone has to be   cleaned and that particular area hair that is the  hair where it is present in that particular area  

has to be shaved. In case if the skin is   oily, clean the site with alcohol and wait till  the alcohol dries. If the skin is visibly soiled,   it should be cleaned with soap and  water. Apply required amount of gel  

to minimize the skin to electrode impedance.  If the healthcare provider is using a readymade   electrode sticky pad, then the center of the  sticky pad should not be pressed because it   may lead to leakage of electrode jelly. Next we are going to see limb leads. Limb leads  

are indicated as RA right arm, LA left  arm, LL left leg, RL for right leg. RA   electrode has to be placed near or above the  wrist joint or in the right deltoid muscle.   LA, that is left arm electrode has to be placed  near or above the left wrist joint or in the left  

deltoid. Left leg LL electrode has to be placed  above the left ankle or in the upper leg.   Right leg, above the right  ankle or above the right leg.   So these are the placements of limb leads in the  right arm, left arm, right leg and the left leg.  

Generally avoid placing electrodes over the  bony prominences, thick muscles or skin folds,   which could interfere the wave transmission. Next, chest electrodes. Chest electrodes are the   electrodes placed over the precordial surface.  Chest electrodes are indicated as V1 to V6.  

All the 6 electrodes are placed over the  precordial surface at a specific location. V1   the first chest electrode is located or is placed  right 4th intercostal space nearer to the sternum.   V2 is placed at left 4th intercostal  space nearer to the sternum.  

Next, we are going for V4. V4 is placed left 5th  intercostal space at the level of mid-clavicular   line. Mid-clavicular line is an imaginary line  that falls from the center of the clavicular   bone downwards in the thorax. After placing  V4 V3 has to be placed in between V2 and V4.  

Next lead is V5. It has to be placed at the  level of V4 that is left 5th intercostal space   but at the level of anterior axillary line that  is nearer to the anterior axillary line.   Next V6. V6 is placed in the same plane as V4  and V5 but at the level of mid-axillary line.  

Once all lead electrodes have been applied,  attach the associated limb and chest leads   with a cable for each lead lying inferior  to the electrode. This has to be done in   order to reduce the tension of the wire. We saw about 12 leads are there, limb leads,  

chest leads, but the color coding in the leads and  the label in the leads are not same universally.   There are two different classification of leads  are there for its color coding as well as for its   labeling. Number one is American Heart Association  labeling method. Here they are labeled chest leads  

as V1 to V6. Limb lead as LA, RA, LL and RL. And the color coding they have indicated as for   chest leads, either it is brown or red,  yellow, green, blue, orange or purple   accordingly. Similarly, for limb leads, they have  given a color coding black, white, red green.  

But there is another classification which  is called as International Electrotechnical   Commission classification. Based on IEC label  the chest electrodes are labeled as C1 to C6.   And limb leads electrodes are labeled as L,  R, F, N. Similarly the color coding are white  

for the chest leads or red, yellow, green, brown  black, purple accordingly. Here for limb leads   the color coding for L it is yellow, for R it is  red, green, it is for F it is green, for N it is   black. So we can see the color colors here.  For right arm it is white for left arm it is  

black. For left, sorry left leg it is red.   For right leg it is green. So this picture follows  the American Heart Association labeling method of   ECG. Similarly, if we are using as per IEC  label, then color code varies accordingly.  

Till now we saw about various ECG leads and  its location, its color coding, its label.   Now we are going to see how to place the chest  electrode exactly in a correct manner. For   that there is a technique to identify the various  position. For that, first the healthcare provider  

must place the finger over the  patient's tracheal rings.   That is this area the healthcare provider has to  place the ring place the finger over the tracheal   ring. From there slowly the healthcare provider  has to come down. The healthcare provider can  

feel a notch, that is yellow color area  which is called as suprasternal notch.   After locating suprasternal notch, that is from  suprasternal notch the healthcare provider has to   come downward which is the sternal bone. It contains three parts manubrium sterni,  

body of the sternum and xiphoid process. When the  healthcare provider moves the finger downward,   he will feel a little elevation or  a lump which is called as angle of   Louis. This angle of Louis plays an important  landmark in locating the ECG chest leads.  

The angle of Louis corresponds to  the second rib on both the side.   Just below the 2nd rib, the space is  2nd intercostal space. Next, 3rd rib,   3rd intercostal space. 4th rib, 4th intercostal  space. 5th rib and 5th intercostal space.  

So in this manner first the healthcare provider  must locate the fourth intercostal space.   So once if the fourth intercostal space is located   right side nearer to the sternum,  V1 electrode has to be placed.  

Exact opposite to the 4th intercostal  space V2 has to be placed. V4   has to be placed in the 5th intercostal space.  In between V2 and V4, V3 has to be placed.   V5 same plane as V4 in the at the  level of anterior axillary line. V6  

in the same plane of V4 and V5 at the level of  mid-axillary line. So the placement of electrode   over the precordial surface is an easy procedure.  Only thing is the location of an angle of Louis is   a must. That technique has to be learnt. After connecting all the leads, we have to  

adjust the paper speed. The normal standard  paper speed of an ECG machine is 25mm/sec.   The ECG paper runs between voltage versus time.  In the x axis it is a time duration. In the y axis   amplitude voltage. If you see the ECG paper,  I can see a small squares with the thin lines  

and a large square with the thick lines. So one small square in a horizontal plane   if is equal to 1mm. The duration is 0.04  second. So one small square is 0.04 second,   then for 5 small square is 5 into 0.04 is 0.2  seconds. That is one large square is 0.2 second.  

Five large square makes 1 second. That is  5 into 0.2 second equal to 1 second. So   1 small square is 0.04 second, I am sorry.   One small square is 0.04 second, one large square  is 0.2 second and 5 large square is 1 second.  

This is for the time duration.  Next if we move on to the voltage,   1 millivolt is equal to 10 small square.  So 10 small square is 1 millivolt.   So before recording an ECG, the paper speed has  to set 25mm/sec. Still there are other speeds  

available in the ECG machine like 50mm/sec,  which is used particularly at the time of   atrial flutter or with a higher heart rate,  the speed has to be adjusted to 50mm/sec.   Next, we move on to the calibration.  After setting the paper speed,  

we have to calibrate the ECG machine by pressing  a calibration button on the ECG machine. If you   press the calibration button, one single  press that is 1 milivolt calibration signal   is expected to produce a rectangle of 10mm  height and a 5mm width on both the sides.  

So whenever recording an ECG,  after checking the paper speed,   the ECG machine has to be calibrated and it has  to be checked for 1 millivolt calibration signal   whether it is producing 10mm height and a  5mm width like this. A rectangle with 10mm  

height and the 5mm width. This is the standard  method to be followed before recording a ECG.   Because if calibration is not done, it may lead  to wrong diagnosis. An additional facility is   available in the ECG machine is filter. Depending  upon the need the filter can be switched on  

or it can be switched off. In case if  there is an evidence of somatic muscle   interference, repeat recording with a filter  on and recording made at 0.67 to 40 hertz.   Always both the sides calibration is advisable  that is from the left hand end as well as on the  

right hand end calibration has to be done. Next we move on to the artefact. Artefacts   are the electrographic alteration not  related to the cardiac electrical activity.   This artefact occur in the ECG wave which may give  a wrong graphical representation. So it has to be  

avoided while recording the ECG. The cause  for the occurrence of artefact might be due to   poor grounding of the device or interference  by the cell phone or due to electric beds   or even do to fluorescent lamps which is  present in the ECG room while recording.  

So fluorescent lamp has to be switched off in  case if we get an artefact in the ECG.   After recording ECG the healthcare provider  must switch off the ECG machine and detach   the ECG cable, inform the patient that ECG  procedure is over and educate that removal  

of ECG electrode may cause mild discomfort.  So after informing, remove the electrodes.   Thank the patient for the ECG recording. Then label the ECG paper that is the   identification, name of the patient, date of  birth, date of recording, sex, hospital number,  

indication of an ECG all has to be mentioned  in the ECG paper. After the entire procedure   wash the hand, that is healthcare provider has to  wash their hands with an antiseptic lotion.   Next we can see what are the other  ECG devices where ECG can be recorded,  

that is wearable ECG recording devices.  Among the available ECG recording devices,   number one is Holter monitor. Holter  monitor is a portable electrocardiogram,   which records the electrical activity of  the heart for a period of longer duration,  

that is from a day to even many days. This Holter monitor is useful in order to   identify certain electrical or ECG changes that  cannot be seen in the exercise testing, or else   to identify irregular heartbeat and palpitation  this Holter monitor plays an important role.  

The other wearable devices smart watch,  which is available in the market,   where it is a ECG recording enabled smart  watch. It combines everything from sleep   tracking features to ECG monitor. So this presentation is to be used as an  

adjunct to other learning methodologies and  not a substitute for appropriate clinical   training and qualification. I would like to thank my institute,   Chettinad Hospital and Research Institute and  NPTEL- Swayam for giving me an opportunity for  

this presentation. And the sources of references  that I have used are Guyton and Ganong.