An electrocardiograph gives a graphic representation and a print out of the changing electrical activity in the heart. The main use of ECG in our practice is for the diagnosis and investigation of arrhythmias, that is the change to the normal heart rhythm, and the ECG gives much more information on the type of arrhythmia and the likely cause can then be gained by listening with a stethoscope. This information is important in the correct treatment of many heart problems and the ECG can also aid the diagnosis of other electrolyte and hormonal imbalances and diseases.