| Properties | Details |
|---|---|
| SFDA Classification | Class IIb |
| Purpose of Use | It is a diagnostic device that measures the electrical activity of the heart during the contraction and relaxation of the heart muscles. |
| Work Location & End-User | Work Location: The electrocardiogram is used in many places in the hospital, whether to monitor the heart's activity during surgeries or even for routine follow-up of some patients. Therefore, the device can be found in family medicine, internal medicine, or surgery clinics. End User: The device can be operated and connected to the patient by any trained nurse in addition to obtaining planning. However, reading the chart needs a specialist doctor, such as a family doctor or internist. In complicated cases, a cardiologist is referred to analyze the result. |
| Parts & Accessories | Parts: １- Electrocardiogram recorder: It is where the electrical signal is processed through electronic components such as amplifiers, filters, and microprocessors. - Usually built-in oscilloscope to display the chart in the screen. It has a display screen. It contains an isolated power generator and a battery for cases where electricity cannot be connected to the device. ２- Conductive wires. ３- Ten electrical sensors within adhesive pads: 12 electrodes are formed: - 3 terminal sensors of 6 poles (I, II, III, aVR, aVL, aVF). - 6 6-pole chest sensors (V1,-V6) Neutral sensor. ４- Contains protection devices in case of need to use an electric shock device. ５- The device also needs a conductive gel to be applied to the patient's skin. |
| Operation | １- When the heart is beating, it produces an electrical current that can be picked up through the sensors connected to the patient's skin. The sensors simply measure the potential difference of a pulse from several directions by measuring the current between two sensors, one positive and the other negative (one pole). ２- The sensors transmit current to the ECG recorder through the connected wires. The signal arrives at a pre-amplifier electronic component. The pre-amplifier compound preserves the characteristics of the signal while protecting the primary amplifier from any high voltages that could harm it. It also consists of an insulating amplifier to isolate the patient's body from the device for the patient's safety from any electric shock. ３- The signal then passes through what can be called a “buffer amplifier.” It balances the signal without changing it. ４- The signal is transmitted to a differential amplifier, which amplifies the signal about 100 times in order for its characteristics to become clear and it can be read without errors. ５- The filters filter the signal so that the frequencies included in the heartbeat signal remain. ６- A feedback network returns the selected frequencies to the amplifier for further optimization. ７- Finally, the Bridge output circuit controls a pen to draw the resulting signal on a thermal paper ８- In the event that the signal needs to be displayed on a display screen, the device contains a microprocessor to convert the signal from analog to digital to be modified and then back to analog to display it. ９- There is also a memory in the device to save information. １０- And a display screen to display the final signal and patient information.   |
| Common Problems | １- Malfunction of the connecting wires. The wires must be replaced with new ones. ２- Failed to print. It is usually due to the thermal papers not being properly placed in the printer. The papers should be positioned so that the mark placed on the paper is against the sensor in the printer. ３- The battery sign does not light up (when the ECG machine is running on battery). Remove the battery and measure the voltage in it. If it is within normal, then the battery is good. The circuit for the battery tag may be damaged and should be replaced. The presence of an intruder distorting the wave. In this case, you must know if the cause is from inside or outside the machine. Use the calibration key on the keyboard on the device. Set the "lead selector" to the calibration position and the "paper feed" to the recording position. If the pen starts drawing, move the calibration switch. If the drawing is distorted (the drawing must be a straight line), then the machine is faulty. If the EKG isn't distorted, it's most likely because the sensors aren't well connected to the body or there are other devices around the ECG. ５- Unsteadiness of the drawing on a straight line (shifting the drawing from the specified place on the paper). Run the device on battery, if the graphic improves, the problem is with grounding. ６- If there are distortions in one or some parts of the drawing but not all of it, the problem is usually from not connecting the sensors well or there is a problem with the connected wires. And the problem may be that the patient's skin is not ready. ７- Complete failure of the electronic plate due to moisture and dust. The device must be completely replaced and the new device should be placed in a place safe from moisture and dust. |
| Manufacturers | • Nihon Kohden. • GE Healthcare • Philips. • Bionet. • Burdick. • Shenzhen. • Axion. |
| Sources | • Saudi Food and Drug Authority Document • NHS • Northeastern University • Healthfully • OnlineBiologyNotes • ECGWAVES • Medicalequipment • Directorate of Health Services |
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