How is a heart attack diagnosed?   Any doctor, nurse, or health care professional, will send a patient straight to hospital if he/she suspects the person may have a heart attack. In hospital several tests may be done:   ECG (Electrocardiograph) An ECG is a medical device that monitors the electrical activity of the heart muscles. Our hearts produce a small electric signal at every beat. A heart specialist (cardiologist) can use this device to see how well the heart is functioning, whether there is any damage to the heart muscle, or abnormalities with the heart rhythm. A doctor can tell, when checking the data coming from the ECG, whether the patient has had a heart attack recently, or even earlier.   Cardiac enzyme tests When a person has a heart attack some enzymes make their way into the bloodstream. A blood test can detect these enzymes. Usually, enzyme blood levels are checked regularly over a few days.   Chest x-ray This can be useful to see if the heart has any swelling.