Cardiology Bodies Agree New Universal Definition of Heart Attack

Four major cardiology organisations — the European Society of Cardiology (ESC), American College of Cardiology (ACC), American Heart Association (AHA) and World Heart Federation (WHF) — have jointly published the Fifth Universal Definition of Myocardial Infarction (MI), or heart attack, presented at ESC Congress 2026 on August 30.

Myocardial infarction is one of the most common cardiovascular disorders, with an estimated prevalence of 3.8% in people younger than 60 and 9.5% in those 60 and older. ESC Chair Professor Nicholas Mills of the University of Edinburgh said the previous system used complex numerical categories, such as "type 2" or "type 4c," that were not always easy to apply in clinical practice, leading to inconsistent diagnosis and treatment.

The updated system sorts every heart attack into one of three categories based on its underlying cause: primary MI, which arises spontaneously, most often from a ruptured plaque in a coronary artery but sometimes from a tear in the coronary wall or a spasm; secondary MI, which comes from an imbalance between the heart's oxygen supply and demand caused by another condition, such as very high or low blood pressure; and procedure-related MI, which occurs within 30 days of a cardiac procedure such as coronary stenting or bypass surgery.

ACC/AHA Chair Professor Kristin Newby of Duke University Medical Center said clinicians can now discuss the actual cause of a heart attack with patients rather than complex numerical types. The new classification also aligns with the World Health Organization's ICD-11 coding system, which WHF Chair Associate Professor Sarah Zaman of the University of Sydney said should standardise data collection and could help expand research into under-studied causes, such as spontaneous coronary artery dissection, a condition that occurs mostly in women and is currently underdiagnosed.