Global change in heart attack diagnosis: what will change in emergency rooms in Israel?
Leading cardiology organizations worldwide have published the "Fifth Universal Definition of Myocardial Infarction," replacing the previous numerical classification with three clear clinical categories. The goal of this update is to move beyond merely confirming a heart attack to accurately identifying its cause, thereby tailoring treatment. The document was prepared by the European Society of Cardiology (ESC), the American College of Cardiology (ACC), the American Heart Association (AHA), and the World Heart Federation (WHF).
A significant change in the way doctors around the world define a heart attack: four leading cardiology organizations published the "Fifth Universal Definition of Myocardial Infarction," which replaces the numerical classification used until now with three clearer clinical categories. The goal is not only to determine that a heart attack has occurred, but to understand more accurately what caused it, and accordingly to adapt the investigation and treatment. The new document was published on behalf of the European Society of Cardiology (ESC), the American College of Cardiology (ACC), the American Heart Association (AHA), and the World Heart Federation (WHF). It was published in JACC and the European Heart Journal and represents an update to the previous universal definition from 2018.
Not every heart attack is caused by the same reason
One of the key changes is the cancellation of the previous numerical classification of myocardial infarction and its replacement with three groups based on the mechanism that caused the event. A primary infarction is an event that occurs spontaneously as a result of an acute problem in the coronary arteries. The most common cause is a rupture or injury to an atherosclerotic plaque and the formation of a blood clot, but the group also includes other mechanisms in the coronary arteries. A secondary infarction occurs when the heart does not receive enough oxygen relative to its consumption as a result of another acute medical condition. Among the conditions that can create such an imbalance are, for example, severe anemia, a drop in blood pressure, a lack of oxygen, or significant heart rhythm disturbances. The third category is an infarction related to a medical procedure, meaning an event that occurs as a complication of an invasive cardiac procedure or heart surgery. The goal of the change is to adapt the diagnosis to what the doctor actually sees in the patient and make it more meaningful for further treatment.
High blood test results do not always mean a heart attack
The new definition also sharpens an important point regarding troponin — a protein released into the blood when there is damage to heart muscle cells and used as one of the main indicators in emergency rooms for diagnosing a heart attack. An elevated level of troponin is not sufficient in itself to determine that a person has had a heart attack. According to the new definition, a diagnosis of infarction requires evidence of acute damage to the heart muscle along with evidence that the damage was caused by ischemia — a lack of blood and oxygen supply to the heart muscle. Therefore, doctors must look at the overall picture: the patient's symptoms, changes in the ECG, troponin levels, and in appropriate cases, also imaging tests of the heart and coronary arteries. This distinction is important because troponin levels can also rise in conditions that are not a heart attack, including acute heart failure, pulmonary embolism, rhythm disturbances, inflammation of the heart muscle, and other severe medical conditions.
An especially important change in diagnosing women
One of the significant innovations in the document concerns the differences between women and men. The new recommendations emphasize the use of troponin threshold values adapted to the patient's sex. The reason for this is that troponin levels in the healthy population are generally lower in women compared to men. Using a uniform value for both sexes may cause damage to the heart muscle in some women to go undetected. The authors of the document note that sex-adapted threshold values are intended to prevent systematic bias and under-diagnosis of infarction and other conditions that cause damage to the heart muscle among women.
Even a heart attack without an artery blockage gets more attention
The new framework emphasizes that not every infarction is caused by the "classic" blockage that many know. Among the possible mechanisms for a primary infarction are also spontaneous coronary artery dissection (SCAD), artery spasm, and coronary artery embolism. In appropriate cases, experts recommend using imaging and functional tests to identify the exact mechanism. This point is especially significant because some of these mechanisms also appear in patients who do not fit the known profile of a person with significant atherosclerosis.
What does this mean for patients in Israel?
The document is an international consensus and not a new Israeli guideline in itself, so it does not mean that every protocol in emergency rooms in Israel changes immediately. However, the Israel Heart Association was among the national associations that participated in the review process of the document, so the new definition has clear relevance for medicine in Israel as well. In practice, the change may make the diagnosis "heart attack" more accurate: instead of settling for one name for events caused by different mechanisms, the doctor is required to understand whether it is a primary problem in the heart arteries, a result of another acute disease, or a complication of a medical procedure. For the patient, the difference is not just semantic. The reason why the heart muscle was damaged can affect the tests required, the treatment given, and the follow-up. The central message of the new definition is simple: "heart attack" is not one disease that always looks and behaves the same way, and the better one understands what caused the event, the more accurate one can be in diagnosis and treatment.
