The Definition for a Heart Attack Just Changed—and It Could Help Women in a Big Way

Most people are aware of the general mechanism behind a heart attack : Blood flow to the heart is reduced or blocked, causing damage to the organ. But the exact medical definition is actually a lot more complicated; it classifies heart attacks into different categories, each with its own urgency and treatment plan.

Now, four major cardiology associations around the world have agreed on a new definition for heart attack—and it could help more women get diagnosed so they can get the timely treatment they need.

Meet the experts: Ravi Shah, M.D ., associate director of the cardiac care unit at Northwell's Lenox Hill Hospital; Sanjiv Patel, M.D ., interventional cardiologist at MemorialCare Heart & Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA

The new definition comes courtesy 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's a "simplified" classification system that breaks heart attacks, a.k.a. myocardial infarction, into three categories and changes priorities and diagnostic criteria for them. That includes increasing emphasis on some less common forms of heart attack, which commonly affect women more than men, according to Sanjiv Patel, M.D ., interventional cardiologist at MemorialCare Heart & Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA.

This updated definition of a heart attack follows the 2025 " Great Debate " in the European Heart Journal that spotlighted the vagueness of the previous definition and the complicated medical jargon that made it tough to make shared decisions with patients, says Ravi Shah, M.D ., associate director of the cardiac care unit at Northwell's Lenox Hill Hospital. "I would have some patients say, 'I had a stage four heart attack, so it wasn't a 'bad' heart attack?'" Dr. Patel says. "It's confusing for patients."

To be clear, any heart attack is still a heart attack—and all heart attacks are serious. But the new definition reclassifies types of heart attacks and creates a simpler understanding for everyone involved. Here's how it works, plus why doctors say it's a good thing for women.

What's the new definition of a heart attack?

The new guidelines break heart attacks into three categories:

Primary : This happens suddenly and is caused by severe reduction or a blockage of blood flow to the heart.

Secondary : This occurs due to an imbalance in oxygen supply and demand in the heart due to another acute condition.

Procedure-related : These happen as a complication from surgery.

The new definition also changes the threshold for women to be diagnosed with a heart attack based on a level of a protein called troponin in their blood, which is released when the heart is injured. "Baseline normal levels of troponin are lower in females than males," Dr. Patel says. But previous definitions had a universal baseline for both sexes.

As a result, women having a heart attack were at a greater risk of being misdiagnosed than men when doctors looked at troponin, he explains. The new changes provide a lower limit for women, which can catch heart attacks that the previous levels may have missed.

Why are these changes helpful for women?

There are a few reasons why these changes can benefit women. The new definition emphasizes identifying the underlying cause of a heart attack , Dr. Shah says. Take spontaneous coronary artery dissection (SCAD), which occurs when a tear in the heart's artery blocks blood flow to the heart. Women make up about 90% of its cases, and it's often under-recognized and misdiagnosed, he says. The previous definition put SCAD into an "ambiguous" category, Dr. Shah points out. "This new framework moves SCAD into the primary myocardial infarction definition and will hopefully help increase prompt recognition and diagnosis," he says.

The sex-specific troponin thresholds can also help detect a heart attack in women sooner, Dr. Shah says. Not only that, the new definition encourages the use of imaging to define the cause of heart attack. "Both will help address the current disparities in the diagnosis and treatment of heart attacks in women," he adds.

Women are more likely to have signs of a heart attack that are considered "atypical" compared to men, who more often present with the classic chest pain and pressure. This makes it more important to dive deeper when they're not well, Dr. Patel says. "They might have sharp pain, nausea , or shortness of breath compared to the traditional symptoms you expect," he says. "Sometimes people might not consider those symptoms as someone is having a heart attack, and they might not get properly treated." The new definition doesn't necessarily change awareness for patients of these symptoms, but it does provide more tools for doctors to detect heart attacks in people who may not have classic signs.

What to do if you suspect you're having a heart attack

While the definition for diagnosis has gotten fine-tuned, the guidance around what to do if you are having a heart attack hasn't changed. "In cardiology, we say 'time is muscle'—prompt diagnosis and treatment of a heart attack is crucial," says Dr. Shah.

If you suspect you're having a heart attack, he recommends getting to the emergency room ASAP. Dr. Patel suggests being evaluated if you're unsure if you're having a heart attack, too. "Because of the atypical nature of symptoms in females, they tend to brush it off as 'just' stomach pain or something else," he says. "But when they realize something is wrong 1.5 hours later, they're already 1.5 hours into a potential heart attack, which is not a great thing. Time matters."

While it may be inconvenient to take a trip to the ER, Dr. Patel says it's important to get checked out. "If it's not a heart attack, it's not—great," he says. "But if it is, it's a big deal. You can save your life, and save yourself a lifetime of medical problems if you get diagnosed and treated quickly."