PowerPoint Presentation On Electrocardiograph

PPT On Electrocardiograph

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Electrocardiograph Presentation Transcript:

1. HISTORY
As long ago as 1855, researchers Kollicker and Mueller discovered that when a motor nerve from a frog’s leg was laid over its beating heart, the leg would kick with a regular beat. Alexander Muirhead is reported to have attached wires to a feverish patient's wrist to obtain a record of the patient's heartbeat in 1872 at St. Bartholomew's Hospital. This activity was directly recorded and visualized using a Lippmann capillary electrometer.

2. NEED OF ECG??
Initially there was no device to monitor functioning of heart. Every heart problem was only detected by monitoring heart rate. So doctors found a need of detecting the electrical activity of heart thus setting a standard electrical wave for proper functioning of heart. So a device has to be made to plot this wave.

3. ELECTROCARDIOGRAM
The electrocardiogram (EKG) is a representation of the electrical events of the cardiac cycle. Each event has a distinctive waveform, the study of which can lead to greater insight into a patient’s cardiac operations.

4. Timing of intervals and waves P wave - 80 ms. PR interval - 120 -200 ms. QRS complex - 80 - 120 ms. T wave - 160 ms. QT interval - 300 - 430 ms. U wave – low amp. , not always seen.

5. ECG – machine
An ECG machine is called an electrocardiograph. It is a diagnostic tool used in assessing the cardiovascular system. It is basically an amplifier that amplifies the heart’s electrical impulses from skin.

 6. Major Components
Special graph paper Electrodes Electrolyte paste An amplifier Storage and transmission device The ECG machine Connecting wires

7. GRAPH PAPER
The output of an ECG recorder is a series of several graphs, representing each of the leads with time represented on the x-axis and voltage represented on the y-axis. A dedicated ECG machine would usually print onto graph paper which has a red background pattern of 1mm squares, with bold divisions every 5mm in both vertical and horizontal directions. It is standard to represent each mV on the y axis as 1cm and each second as 25mm on the x-axis (that is a paper speed of 25mm/s). At a paper speed of 25 mm/s, one small block of ECG paper translates into 40 ms. Five small blocks make up one large block, which translates into 200 ms. Hence, there are five large blocks per second. A standard signal of 1 mV must move the stylus vertically 1 cm, that is two large squares on ECG paper.

8. ELECTRODES
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit. ECG machine unipolar bipolar Forms - plate, suction, fluid column, flexible Made of stainless steel, German silver, or nickel, silver and silver chloride.

9. AMPLIFIERS
ECG amplifiers are needed to convert the weak electrical signal from the body into a more readable signal for the output device. A differential amplifier is useful when measuring relatively low level signals. The sections of the amplifier which receive direct signals from the patient are separated from the main power circuitry of the rest of the EKG machine.

10. For more info. please refer our PPT. Thanks.