A New Heart Attack Classification: Why It Matters for Women
A heart attack is often described as a blocked artery. But problems with blood flow to the heart can happen for several reasons, and understanding the cause helps guide care.
In August 2026, four major cardiovascular organizations published the Fifth Universal Definition of Myocardial Infarction. The updated document provides a simpler way to classify myocardial infarctions, or MIs, based on their cause and clinical setting.
Developed by the European Society of Cardiology, American College of Cardiology, American Heart Association, and World Heart Federation, the framework may also bring greater attention to underdiagnosed conditions that affect women.
What Changed in the Heart Attack Classification?
The previous system used numbered MI types. The updated framework groups myocardial infarctions into three clinical categories.
Primary Myocardial Infarction
A primary MI begins with an acute problem in a coronary artery. The most common cause is the rupture of plaque within the artery. Other causes include a coronary artery tear, spasm, or clot.
Secondary Myocardial Infarction
A secondary MI occurs when another acute condition creates an imbalance between the oxygen the heart needs and the oxygen it receives. Examples include a very fast heartbeat or blood pressure that is extremely high or low.
Procedure-Related Myocardial Infarction
This category covers an MI that occurs as a complication of a cardiac procedure, such as coronary stenting or bypass surgery. The diagnosis requires clinical assessment; having a procedure alone does not mean an MI has occurred.
SOURCE: American Heart Association – 2026
Why Does This Matter for Women?
One condition receiving attention is spontaneous coronary artery dissection, or SCAD. This involves separation within the wall of a coronary artery and can reduce blood flow to the heart muscle.
SCAD predominantly affects women and remains underdiagnosed. The updated classification recognizes it as a cause of primary MI and may support more consistent data collection and research.
The new framework does not create a separate heart attack category for women. It encourages a clearer understanding of the different mechanisms that can cause an MI.
What Role Do Blood Tests Play?
The updated document also addresses cardiac troponin, a blood marker used to detect heart muscle injury. It uses sex-specific reference limits, meaning the thresholds for identifying injury differ for women and men.
An elevated troponin result alone does not establish that a heart attack has occurred. Clinicians interpret the result alongside symptoms and other findings to determine the cause of the injury.
What Does This Mean for Patients?
The goal is to make an MI diagnosis easier to understand and more useful in guiding care. Knowing why it happened can help patients understand the need for further testing and treatment.
The update does not change the need for urgent care. If you think you may be having a heart attack, call 911 immediately. Do not wait for symptoms to become severe.
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Dr. Julien has performed more than 40,000 vascular procedures across a 30-year career. Double board-certified in Interventional Radiology and Diagnostic Radiology by the American Board of Radiology, he is the co-founder and past president of the Outpatient Endovascular & Interventional Society, a national faculty speaker at SIR, TCT, VIVA, and the Southeastern Angiographic Society, and a published author. Named a Boca Magazine Top Doctor 2025.
