If you are planning to buy an ECG machine, you have come to the right place!
Read this article thoroughly to guide yourself about buying the most suitable ECG machine.
Historically, the first human Electrocardiogram was recorded in 1887, which led to the development of the first ECG machine in 1901 by Willem Einthoven, who later received the Nobel Prize for this achievement. Later in 1927, the general Electric Company developed an ECG machine that utilized vacuum tubes for amplification of electrical signals. Today’s ECG machines are highly sophisticated equipment that uses solid-state electronic components, which not only makes them portable but also capable of recording cardiac rhythm patterns while wearing them (wearable ECG machines).
Parts of an ECG Machine
Technically speaking, an electrode is a conductor that makes contact with a non-metallic part of a circuit (human skin in this case). In ECG machines, the electrodes used are mostly made of silver or silver chloride, since this material has the ability to stabilize electrode potential when in contact with a living tissue. Some ECG machines come with more than one type of electrodes.
These are shielded cables that are connected to the electrodes on one side and to the ECG machine (amplifier) on the other. Shielding prevents leakage of current and hence ensures a more reliable ECG pattern. Connecting wires transmit electric signal from electrodes to the amplifier.
An ECG amplifier consists of a “buffer amplifier” and a “pre-amplifier/differential amplifier”. The amplifier parts of an ECG machine are separated from the main machine unit; this is done to prevent any electrical shock from reaching the patient (in case an electric malfunction occurs).
The electrical signals coming from electrodes enter the buffer-amplifier, where they are stabilized and translated. The signals are then fed to the differential/pre-amplifier which reduce the noise and amplifies them by about 100 times, thus making them readable.
The output from amplifier is displayed or recorded using various output devices. These may include printers, paper strips, computer monitors, digital displays, electronic ECG records etc.
Key features to consider when buying an ECG machine
Size of ECG machine
ECG machines come in various sizes since they are designed for use in different clinical situations. A Holter ECG monitor is a wearable ECG machine that allow recording of cardiac rhythm for an extended period of time. These devices are battery operated and batteries can be charged before monitoring is carried out.
Machines are comparatively larger size are routinely used in hospital settings; most being portable.
Power source & Battery backup
A rapidly emerging trend is the use of re-chargeable batteries in ECG machines. This not only increases convenience, but also decreases dependency on power supply to carry out ECG recording. In countries where electric power is scarce, rechargeable ECG machines have found wider acceptance in medical community. However, rechargeable batteries have to be replaced once they have reached the end of their lives. Therefore, you need to make sure that your supplier provides the batteries of the equipment that is being sold to you or your hospital.
The type and size of ECG machine paper
Different varieties of paper are used in ECG machines. Different brands and models utilize different ECG paper types. Sometimes ECG paper comes in rolls, while in other cases it comes as sheets that are joined together and then packed in a “ Z-fold “ pattern. Different widths and lengths are possible; therefore it is always a good idea to read the instructions before your place your order when buying ECG paper. The size/thickness/circumference of paper rolls may differ; hence only the right size will fit in the ECG machine’s feeder. Using paper rolls of inappropriate size may affect the working of ECG machine and hence ECG machine’s reading may become faulty. Always ask about paper supply and cost, before you make your decision to buy an ECG machine.
Some machines have dedicated keyboards to enter patient data and also to perform various functions when performing ECG. However, machines having complete keyboards tend to be expensive than ordinary machines. So, you should choose a machine based on your budget and also your labeling requirements of the ECG.
Display or Screen
Older machines were devoid of LCD displays and only LEDs or bulbs were used as indicators that assisted ECG technicians when performing ECGs. However, modern machines usually contain high resolution digital displays that make possible the visualization of ECG patterns before they are printed. This feature is very useful, since it prevents printing of faulty ECGs and saves a lot of hassle and paper. Moreover, in situation where you are out of paper, you can still see the ECG pattern on ECG machine’s digital display to make clinical decisions.
ECG Software Interpretation
As new algorithms to detect abnormalities in ECG patterns are becoming more and more perfect, automatic interpretation of ECGs is becoming increasingly common. Although it is impossible to rely on software interpretation of ECG completely; it is a great feature since it provides an alternate opinion regarding the diagnosis in question.
Connectivity to other equipment
Another important aspect to consider is the possibility of connecting your ECG equipment to other digital devices. Data sharing between devices is becoming increasingly common and if your ECG machine has the capability to connect with other electronic devices or health equipment – this is a plus!
Smart-phone based electrocardiography devices are also becoming available in some parts of the world. Devices that can provide 12-Lead recording of ECG on smart-phones have already been developed.
Is your staff comfortable with using a PC based ECG system?
Some ECG machines are designed to provide ECG output through computers. Although this is very convenient for many; others who lack the skill to operate computers, may find this distressing. Consequently, you should be aware of your hospital staffs’ preferences and capabilities, before you plan to buy an ECG machine.