ESC: Experts Replace Complex Heart Attack Numbering with Three Clear Categories

Leading international cardiology organizations have developed a universal definition of myocardial infarction, moving away from the complicated numbering system previously used to classify heart attacks. The new classification, presented at the 2026 Congress of the European Society of Cardiology (ESC), divides myocardial infarctions into three broad categories designed to make diagnosis and treatment easier.

A myocardial infarction occurs when part of the heart muscle dies because its blood supply is disrupted. It affects an estimated 3.8% of people under 60 and 9.5% of those over 60. In the past, doctors used a complex system that referred to different types of heart attacks by numbers, such as type 1 or type 4, which could be confusing for both patients and healthcare professionals.

Researchers from the University of Edinburgh in the UK, Duke University Medical Center in the US, and the University of Sydney in Australia have now proposed a simpler classification: primary, secondary, and procedural myocardial infarctions.

Primary heart attacks occur spontaneously as a result of problems affecting the coronary arteries. Secondary infarctions are caused by an imbalance between the heart’s oxygen supply and demand, for example during significant changes in blood pressure or other physiological stress. Procedural infarctions occur in connection with medical interventions and are defined as those developing within 30 days after cardiac surgery or procedures.

“We will no longer have to discuss strange numbers with patients. We can now explain the cause of their heart attack in straightforward terms, helping people understand their condition and the need for further treatment,” said Christine Newby, a professor at Duke University Medical Center.

Linking the new definition to the International Classification of Diseases (ICD-11) could also help doctors collect more accurate statistics and investigate rare causes of myocardial infarction. One example is spontaneous coronary artery dissection (SCAD), a dangerous tear in the wall of a coronary artery that disproportionately affects women. SCAD can be difficult to diagnose because its symptoms may not fit neatly into older classification systems.

The simplified framework could benefit both healthcare professionals and patients by making the causes and types of myocardial infarction easier to communicate and record. As the new standards are adopted, researchers hope they will improve the recognition of less typical forms of heart attack and ultimately contribute to better patient outcomes.