A revised global definition of a heart attack launched by international cardiovascular organizations introduces sex-specific diagnostic criteria and a simplified three-category classification system, addressing longstanding diagnostic gaps for women according to the World Heart Federation and the Heart Foundation.
New Three-Category Heart Attack Classification System Replaces Numerical Types
Medical experts have overhauled how acute coronary events are categorized worldwide. Until now, clinicians classified heart attacks using a numerical system spanning five types. According to joint statements from leading international groups including the World Heart Federation (WHF) and the European Society of Cardiology, that numerical system is replaced by three clinical categories.
The revised Fifth Universal Definition of Myocardial Infarction (UDMI) groups cases into primary myocardial infarction, secondary myocardial infarction, and procedure-related myocardial infarction. Baker Heart and Diabetes Institute professorial research fellow Tom Marwick stated in reporting by the Australian Broadcasting Corporation (ABC) that this update considers the underlying cause of a cardiac event and simplifies communication with patients.
Did You Know? Cardiovascular disease remains one of the leading causes of death for Australian women, yet research shows women experiencing acute coronary events have historically faced longer diagnostic delays than men.
Sex-Specific Troponin Thresholds Improve Women’s Heart Health Outcomes
The updated guidance addresses diagnostic disparities by establishing sex-specific thresholds for cardiac troponin, a protein released into the bloodstream when the heart muscle is damaged or inflamed. According to WHF UDMI Taskforce Chair Associate Professor Sarah Zaman, speaking to newsGP, women naturally have lower normal cardiac troponin levels than men. Using high-sensitivity assays alongside sex-specific reference ranges ensures clinicians account for these biological differences.
Heart Foundation head of clinical strategy Natalie Raffoul noted in ABC reporting that these sex-specific ranges help doctors effectively identify heart attacks when female patients present with symptoms. This aligns directly with the Heart Foundation’s Australian clinical guidelines for diagnosing acute coronary syndromes.
Recognizing SCAD and Other Female-Dominant Causes of Primary Infarction
Primary myocardial infarction now explicitly encompasses conditions that occur more frequently in women, such as spontaneous coronary artery dissection (SCAD), coronary artery spasm, and coronary embolism. According to Associate Professor Zaman, these presentations are now recognized alongside traditional atherosclerotic plaque ruptures and blood clots.
SCAD involves a tear in a coronary artery wall and primarily affects women with few traditional cardiovascular risk factors. An Australian study cited by the ABC indicates that nearly one in four acute coronary syndrome events in women under the age of 60 stem from SCAD. The condition is frequently associated with extreme stress, menopause, or childbirth.
Melbourne GP Associate Professor Ralph Audehm told newsGP that while primary care physicians generally refer acute cases to emergency departments, receiving clear discharge summaries detailing the exact underlying cause—such as atherosclerosis versus SCAD—remains vital for ongoing patient management and secondary prevention.
Frequently Asked Questions
What is the Fifth Universal Definition of Myocardial Infarction?
It is a revised global framework developed by the World Heart Federation, European Society of Cardiology, and other bodies to classify heart attacks into three clear clinical categories based on underlying causes and introduce sex-specific diagnostic criteria.
Why do sex-specific troponin thresholds matter for women?
Women typically exhibit lower baseline cardiac troponin levels than men. Utilizing sex-specific reference ranges allows emergency and primary care clinicians to detect heart muscle damage more accurately in female patients.
What is Spontaneous Coronary Artery Dissection (SCAD)?
SCAD is a type of heart attack caused by a tear in the wall of a coronary artery rather than a cholesterol plaque buildup. It disproportionately affects younger women, often during or after pregnancy, and is now formally grouped under primary myocardial infarction.
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