An electrocardiogram (ECG) is a medical test that detects heart problems by measuring the electrical activity generated by the heart as it contracts. A doctor may recommend an ECG for people who may be at risk of heart disease because there is a family history of heart disease, or because they smoke, are overweight, have diabetes, high cholesterol or high blood pressure. A doctor may also recommend an ECG for people who are displaying symptoms such as chest pain, breathlessness, dizziness, fainting or fast or irregular heartbeats.The ECG is a safe and non invasive procedure with no known risks.