Electrocardiographs - Basics
| Abbreviation / other names
|
ECG Electrocardiogram (In America it is sometimes called EKG) Electro = electrical activity |
| What does it do? |
It records and measures the electrical activity of the heart.
It is used to measure the heart rate and to diagnose heart problems. |
| Physiology |
The cells inside the heart muscle conduct electrical current. Some cells in the heart (the pace-maker cells) charge by themselves regularly and they cause the other cells to charge. A current flows through the heart muscle in a particular way. Every time this happens the heart muscle contracts and pumps the blood – “heart beat”. |
| How it works |
The tissues in the human body are electrical conductors and
when the electrical current flows in the heart we can measure
it in the surface of the body. ECG electrodes are made of silver-silverchloride and they are stuck to the skin together with ECG gel. The electrical signals from the heart are picked up by these electrodes and measured and recorded by the ECG machine. |
| Units of measurement |
Beats per minute (BPM) Measurement of amplitude in mV |
| Typical values |
Adults: 50 – 90 BPM Neonates: 120 – 180 BPM The repetitive electrical signal produced by the Heart and measured at the patient electrodes is approx. 1 mV in amplitude. |
| Picture of equipment |
|
 GE mac5000 |