You may have come across an ECG machine in the hospital. So, what does an ECG machine do? To understand it, you need to be familiarized with the term electrocardiogram. The term electrocardiogram (ECG) is the combination of three terms. They include electricity, heart, and gram which refers to visualization. So overall the term states that it is the visualization of the electrical activities of the heart with the help of graph paper. The graph shows the depolarization of the signal through the heart. The term ECG is interchangeable with the term EKG (elektrokardiogram). Both of them are the same thing. However, ECG is an English word but EKG is a German word. Here we will be talking about the operation, handling, and maintenance of the ECG machine. Finally, we will discuss the price and the supplier for you to purchase the machine in Kathmandu, Nepal.
How does an ECG machine work?
To understand the working mechanism of an electrocardiogram, I suggest you go through this video.
ECG Machine Types
When we talk about the types of ECG machines that we want to purchase, four types of machines come to our mind. They are the single-channel, three-channel, six-channel, and twelve-channel ECG machines. So now let us make some comparisons between the four of them.
1. Single Channel ECG Machine
The term channel refers to the waveform. So the single-channel means that the machine will print a single waveform at a time. This is due to the fact that it has got a single amplification and recording system. This is the oldest and the simplest form of the ECG machine. The machine is cheaper than the other types. But due to its printing ability, it is being replaced by the other models.
Since there are twelve waveforms in total, the machine will print twelve channels, one at a time. So, the printing format becomes 1 X 12. Due to these reasons, the ECG paper will be narrower and longer in length. The width of the paper is around 50 mm.
2. 3 Channel ECG Machine
As the name suggests, the machine prints three waveforms at a time. There are four sections in total. Thus the total waveforms become twelve. The first section will have I, II, and III waveforms. The second section will have aVR, aVL, and aVF waveforms. The third one will have V1, V2, and V3 waveforms. Finally, the fourth section will have V4, V5, and V6 waveforms.
The report format for three-channel ECG becomes 3 X 4 and 3 X 4 +. The term ‘+’ refers to the waveform of a rhythm lead. So, in such a case, the machine will print an extra rhythm lead which you can set in the machine. It may also be operated as a single-channel ECG. However, this feature may not be available in all the models.
The width of the paper becomes wider and the length of the paper becomes shorter than that of the single channel. The size of the paper may be 60 mm, 80 mm, or 100 mm. The paper comes in the form of a roll.
The machine is expensive than the single channel.
3. 6 Channel ECG Machine
It will print the report in 6 X 2 and 6 X 2 + format. Just like before, the machine will also print out the rhythm lead. The graph will have six waveforms in two sections. This makes the process of printing quicker. On top of that, the width of the paper will be greater than that of the 3 channel ECG machine. However, the length of the paper will be comparatively less. The printing paper comes in the shape of the roll with a width of around 120 mm.
This machine is slightly expensive than three-channel.
4. 12 Channel ECG Machine
This is the most advanced and latest form of the ECG machine. This allows printing all the waveforms at the same time. Hence, the printer paper becomes wider but comparatively shorter. The width may range from around 210 mm to 216 mm. The paper is available either in the form of a roll or A4 size paper.
It may even have the feature of printing in different formats such as 1 X 12, 3 X 4, 6 X 2 with or without the rhythm lead. This means that it can have the printing feature of all the above-mentioned models of the machine. It has got the highest response rate in comparison to all other types of machines. Also, the small length for the waveforms will allow the doctors to easily compare and analyze the results.
Installation of the ECG machine
First of all, you need to install all the required accessories in the machine. For this, connect the given earthing cable to the machine. Then connect the power cable and the patient cable.
Now turn on the machine. Once the machine turns ON, you will see the straight lines on the screen. This is because the electrodes have not been attached to the patient. Now connect the chest and limb electrodes onto the distal ends of the patient cable. There are four limb electrodes and six chest electrodes available for operation. You should connect the electrodes systematically. For this, you can see the symbols of the electrodes and tally them with the patient cable.
Put the printer paper into the machine. If you do not place the paper correctly, then the graph will not be displayed on the paper. Similarly, you may be given a USB cable for the transfer of data from the machine to the computer. But, mostly the clients will not make use of the USB cable.
Setting the ECG machine
You may need to check for the following settings in the machine when you are installing the machine for the first time. When the values have been set initially, you may not need to alter those values again.
- Sensitivity (Gain):- Commonly available values may include 2.5/ 5/ 10/ 20/ 40 mm/mV, and Auto (Default). Default is mostly used. The greater is the value, the greater will be the size of the waveform in the machine.
- Paper Speed:- The general value for the speed of the paper during printing may include 6.25/12.5/25/50 mm/s. The speed of the paper should be adjusted properly. Increasing or decreasing the speed may alter the shape of the waveform.
- Man. Mode:- You may set the record and print format of the waveforms. Based on the channels you may have different report formats. We have discussed the report format in the topic of types of ECG machines. For example, the 3 channel ECG machine can have features of 1CH, 1CH +, 3 CH, and 3 CH+. Here 1 and 3 refer to the single and three channels. Similarly, the ‘+’ sign refers to the rhythm lead. That means, along with the normal waveforms, it will also give the waveform of a single rhythm lead.
- Auto. Mode:- It is similar to the manual mode. But here the system is in auto mode.
- Rhythm Lead:- You can select one of the twelve available rhythm leads. Lead II is chosen because it gives a better signal to measure the rhythm.
- Lead Mode:- Mainly two modes of leads are available. They are the standard leads (Wilson) and the European leads (CABRERA). The main difference between these two methods is the arrangement of the waveforms in the ECG paper.
- AC Filter:- The available setting may include 50 Hz, 60 Hz, and OFF. An AC filter helps to reduce the interference of the ECG signal due to the AC supply. So, it is better to turn on this function.
- EMG Filter:- The available settings may include 25HZ, 35HZ, 45HZ, and OFF. An EMG filter helps to reduce the interference of the ECG signal due to the movement of the muscles. So, it is better to turn on this function.
- DFT Filter:- The available settings may include 0.05Hz, 0.15Hz, 0.25Hz and 0.50Hz. A DFT filter resists the drift of the baseline and makes sure that the waveform is in the baseline. So, you should turn on this function.
- Lowpass Filter:- The available settings may include 70 Hz, 100 Hz, and 150 Hz. A lowpass filter helps to reduce the bandwidth of the input signal. By setting the bandwidth, it can filter signals with higher frequency.
You will find many more settings such as display setting, printer setting (manual/ auto mode), etc.
Since the ECG machine measures the heart rhythm and rate, anything that alters this value should be avoided. For example, smoking, drinking alcohol, physical exercise, drinking cold water, certain medications, etc can all alter the normal heart rate. So, the patients who are about to undergo ECG diagnosis should follow these points.
Now, the patient should remove the cloth of the chest. Then he/she should lay down in the bed dorsally. Make sure that the patient does not touch any metal part or the earth during the period of measurement. Connect the terminal of the patient cable to the electrodes.
Clean the skin surface of the patient with alcohol. The presence of sweat and body hair can increase the impedance. However, removing the hair of the patient is practically not possible. So, you need to put some electro-conductive gel on the chest and the limb surface where you should attach the electrodes. This will allow you to reduce the impedance imposed by the skin surface. Then attach the electrodes to the limbs and the chest region.
But before doing so, you need to understand the color-coding given in the patient cables and the electrodes.
The above table shows that according to the color-coding you need to connect the patient cable to the patients with the help of the corresponding electrodes. You can find this information in the electrodes and the patient cable.
The four limb electrodes are attached to four limbs. The remaining six electrodes are connected to the chest surface located above the heart region. Just connect the limb electrodes slightly above the ankle and the wrist.
You can see the following figure for the proper placement of the electrodes.
C1/V1:- Placed on the fourth intercostals space at the right border of the sternum
C2/V2: Placed on the fourth intercostals space at the left border of the sternum.
C3/V3:- Placed on the fifth rib between C2/V2 and C4/V4
C4/V4:- Placed on the fifth intercostals space on the left midclavicular line
C5/V5:- Placed on the left anterior axillary line at the horizontal level of C4/V4
C6/V6: Placed on the left midaxillary line at the horizontal level of C4/V4
(Note:- While placing the chest electrodes, you can place C4/V4 electrode before placing the C3/V3 electrode. This may make your task easier.)
Once all the electrodes have been properly placed on the patient, the waveform will display on the screen of the machine. Then press the print button to get the result of the patient.
There are few things that you need to take care of before and after using the machine. We will discuss a few of those points on this topic.
- Do not operate the machine on a low charge of 15% or less than that. Else, it will reduce the life span of the battery.
- You may use Collins to clean the external surface of the machine. This will allow you to get rid of the dust and contamination. But remember that, using strong solutions such as rectified spirit, can reduce the aesthetic looks of the machine.
- Remove the electrodes and clean them properly. You can use collins to get rid of the gels of the electrodes. If you do not clean the electrodes regularly, then the electrodes will rust and oxidize quickly, In such a case, you will have to get a new set of electrodes from the market.
- Take good care of the patient cable. The cable should not be twisted and bent. It should not be broken. So, hang the cable on the wall when not in use.
- You should not touch the patient or the bed when the machine is in use.
Reasons for error in the ECG result
The graph shows a normal range of ECG for a healthy person. However, the result may not be correct in all cases. One of the reasons is that the person has got an abnormal heart rate. The other reason can be due to the improper handling and operation of the machine.
The working environment should be such that, the patient does not feel any stress during the measurement of the waveforms. The room should be sufficiently wide, and the bed should not be placed tightly. Besides that, the patient is not supposed to move or talk during this process. Else the machine will give an irregular waveform.
The result is highly sensitive to the impedance/ resistance imposed on the signal. The body hair and sweat increase the overall impedance. So, to reduce it, you need to clean the body with alcohol. Then, apply non-expired ECG gel on the body site where electrodes are to be placed.
The error can also occur if the electrodes are placed incorrectly. Similarly, if the connection between the skin and the electrodes is loose or too tight, then the waveform may be irregular. Similarly, the electrodes should not touch each other.
The interference of the ECG signal can also affect the result. For this purpose, the earthing cable should always be connected to the machine during operation. The rusting of the electrodes can lead to signal acquisition. The bed should also be grounded properly. The machine should not be exposed to high-power electric equipment such as X-Ray, MRI, CT-SCAN, etc. The patient should not touch any other metallic parts or the earth. Else, it can alter the flow of the signal.
Some unnecessary settings on the setting menu of the machine can alter the shape of the graph on the graph paper. If the size of the ECG paper is not appropriate, or if the printing head of the machine has been damaged, the machine will not display the proper result.
The error also occurs if the electrodes and the patient cables have been broken.
Fault Finding in Patient Cable
If you are using the ECG machine, then you need to have an idea to check the condition of your patient cables. For this, remove all the electrodes from the distal end of the cable. Then stack the tips of all ten of those cables between your fingers. Once doing so, an irregular and wrong waveform will appear on the display. But, here we are not concerned with the nature of the waveform.
If you see all the waveforms, then you can assure that the cable is working properly. Else it is either defective, or you have not placed the cable properly within your fingers.
This method is most useful in cases, where you do not have patients to check the condition of the cable.
The other method can be by checking the continuity of the cable with the help of a multimeter.
ECG Machine Use
As stated before an ECG machine is necessary for the measurement of the heart’s rhythm and electrical activity. Thus, this helps in the diagnosis of different kinds of diseases such as:-
ECG Machine Price in Nepal
The ECG machine price in Nepal depends upon a number of factors such as the country of origin, features of the machine, and the channel. For example, the price of the 12 channel ECG machine is more than that of the 3 channel ECG machine.
As of this day, the price of the 3 channel ECG machine ranges from Rs 60,000 to 1 lakh. Similarly, the price of the 6 channel ECG machine ranges from Rs 90,000 to Rs 1,50,000. Finally, the price of 12 channel ECG machine is around 2 lakhs.
But you need to keep in mind that I am not an authorized person to decide the price of the machine. The alteration of price can be due to a change in the exchange rate of the foreign currency. So, to get the price of the machine, you need to consult the distributors.
ECG Machine Supplier in Nepal
Different models of the machine are available in the Nepalese market. Some of the most commonly used ECG machines in Nepal are that of EDAN, CONTEC, and BPL Companies.
There are a number of suppliers which deal with these models of ECG. However, I am going to recommend you a few of them. The EDAN product is supplied by Himalayan Medical Technologies Pvt. Ltd. The company is located in Lazimpat, Kathmandu. You can contact the given number (01-4411825) or click on this link.
The supplier of the BPL product is Lumbini Healthcare Pvt. Ltd which is located in Naxal, Kathmandu. You can contact the given number (985-1160315) or click on this link.
One of the suppliers of the CONTEC product is Lumbini Healthcare Pvt. Ltd. However, Bikash Surgical Concern Pvt. Ltd also deals with this product. The supplier is located in Tripureswor, Kathmandu. You can contact the given number (01-4261897, 01-4268429, 01-4268542) or click on this link if you want to purchase this model of machine.