The symptoms of heart attack should be treated as a medical emergency and ambulance and critical care services should be alerted immediately. However, conditions such as indigestion can also cause severe chest pain. Once a patient is admitted to hospital, tests need to be performed immediately to check whether the chest pain is indeed being caused by a heart attack.
An outline of the diagnostic approach to heart attack is given below:
An electrocardiogram (ECG) is the most important tool for diagnosing heart attack. It is usually performed within ten minutes of a patient being admitted to hospital or en-route in the ambulance using a portable ECG machine. An ECG machine measures the electrical impulses generated by the heart muscle. Each heart beat originates at the sinoatrial node (SAN) at the top of the heart in the atrium. This impulse travels via major nerve fibres throughout the heart muscle, instructing them to contract and pump blood. ECG captures these impulses and plots them onto graph paper, which a physician can then interpret to see how well the heart is functioning. Any abnormality may lead to an alteration of the ECG. The test is painless and involves the placement of flat metal discs called electrodes onto the arms, legs and chest. Wires from the electrodes send signals from the beating heart to the ECG machine, which records and translates them onto the graph paper. Particular changes in the pattern generated by ECG machine indicate that a heart attack has occurred. The pattern can also be used to determine which type of heart attack a patient has had.
This can be determined using a measurement called the ST segment. The ST segment corresponds to the degree of heart damage and the higher the ST segment, the more severe the damage is likely to be. Heart attack referred to as ST segment elevation myocardial infarction (STEMI) is the most serious form of heart attack and the patient is immediately assed for treatment to unblock the coronary artery.