1, before the examination can not be full, eat cold drinks and smoking, need to calm rest 20 minutes. 2.The examination should be performed lying down, the whole body muscles should be relaxed, the breathing should be calm, keep quiet, do not talk or move the body position. 3 If you have had an electrocardiogram in the past, you should give the previous report or record to the doctor. If you are taking digitalis, potassium salts, calcium and anti-arrhythmic drugs, you should tell your doctor. 4, according to the condition if you need to do ECG exercise test, you should also note: exercise test should not be done before or one hour after meal; progressive or recent onset of angina pectoris, within one year after acute myocardial infarction, congestive heart failure, severe hypertension, left ventricular hypertrophy, left bundle branch conduction block, pre-excitation syndrome, obvious myocardial ischemia even at rest, old and frail, mobility problems, etc. are contraindicated to do exercise test.