A heart attack, also known as myocardial infarction, occurs when the blood flow to a part of the heart is blocked, causing damage to the heart muscle. This condition is usually diagnosed by a combination of symptoms, electrocardiogram (EKG) results, and blood tests to measure cardiac enzymes.

Typically, when a patient experiences chest pain, the first diagnostic test that is performed is an EKG. An EKG is a non-invasive test that measures the electrical activity of the heart. It can detect abnormal heart rhythms, signs of a previous heart attack, or changes in the heart’s structure or function that may indicate a current heart attack.
If an EKG is abnormal and suggests a heart attack, blood tests are then performed to measure the levels of cardiac enzymes. Cardiac enzymes are proteins released by the heart muscle when it is damaged. The most common cardiac enzymes that are measured are troponin and creatine kinase.
If the EKG and blood tests are both positive for a heart attack, the patient is usually treated with medications and, in some cases, may require an intervention such as angioplasty or bypass surgery. However, there are some cases where the EKG and blood tests are normal, but the patient still experiences symptoms of a heart attack.
One possible explanation for this scenario is that the patient is experiencing a variant form of angina called Prinzmetal’s angina. This type of angina is caused by a spasm of the coronary arteries, which can cause chest pain and other symptoms which are similar to symptoms of a heart attack. The spasm can be transient, which means that by the time the patient arrives at the hospital, the EKG and blood tests are normal.
Another possible explanation is that the EKG and blood tests are not sensitive enough to detect a heart attack. In some cases, the damage to the heart muscle may be small or localized, and the EKG and blood tests may not be able to detect it. This can occur in patients with diabetes or chronic kidney disease, as these conditions can affect the accuracy of the tests.
Finally, it is also possible that the patient is experiencing symptoms of a heart attack, but the cause is not related to the heart. For example, pulmonary embolism (a blood clot in the lungs) can cause chest pain and shortness of breath that can be mistaken for a heart attack. Other conditions, such as gastroesophageal reflux disease or anxiety, can also cause chest pain which is similar to a heart attack.
In conclusion, while an EKG and blood tests are important diagnostic tools for a heart attack, there are situations where they may not be able to detect the condition even when a patient is experiencing symptoms. Therefore, you need to seek medical attention if you experience any signs or symptoms of a heart attack, such as chest pain, shortness of breath, or nausea, even if the diagnostic tests come back normal. Your healthcare professional can help determine the cause of your symptoms and provide appropriate treatment.