A computerized stress electrocardiogram (ECG) is a medical test that measures and records the electrical activity of the heart during physical activity.
The heart is a muscular organ that beats rhythmically to pump blood and deliver oxygen throughout the body. The sinoatrial node (SA node) sends signals to the muscle fibres of the heart telling them when to contract. Each contraction is one heartbeat. The heart works harder under stress, and requires more oxygen. Any deficiency in the supply of oxygen to the heart muscle can be identified with a stress electrocardiogram.
An ECG is performed to assess the heart's electrical activity for abnormalities, such as unexplained chest pain, shortness of breath and irregular heartbeats (palpitations). Some of these symptoms are brought on only with activity and may be missed on a regular electrocardiogram. It also indicates your level of fitness and may be used to assess the effectiveness of treatment.
Before an ECG, a physical examination is performed to assess whether you are physically fit to carry on with the test. Prior to the test, you are advised not to eat, drink or smoke for 2 hours. Electrodes are placed on the skin of your chest. You are then asked to run on a treadmill with progressive difficulty until your heart rate reaches a target level or you start to experience symptoms such as chest pain. Please inform your doctor if you feel weak, faint or experience chest pain while on the treadmill, in which case, you are made to stop the test immediately. ECG is measured until your heart returns to normal. Following the test, you may return to your regular activities.