Traditionally, most heart attacks have been blamed on clogged arteries causing atherothrombosis – where blood clots block flow to the heart. But recent research suggests we may be underestimating the role of other causes, particularly in younger adults, reports ScienceAlert.
Scientists from the Mayo Clinic in the US analysed 1 474 heart attack cases in people aged 65 or younger, recorded between 2003 and 2018, and by carefully reviewing medical records and imaging, were able to identify a primary cause behind each case.
Atherothrombosis accounted for 75% of heart attacks in men, which wasn't surprising. In women, it was the cause of only 47% – which has major implications for the prevention and treatment of heart attacks.
“This research shines a spotlight on heart attack causes that have historically been under-recognised, particularly in women,” said cardiologist Claire Raphael.
“When the root cause of a heart attack is misunderstood, it can lead to treatments that are less effective, or even harmful.”
Among the other factors significantly contributing to heart attacks were spontaneous coronary artery dissections (SCADs), where tears in artery walls collect blood, embolisms and other stressors acting on the body (like anaemia).
The team also found that many SCAD-related heart attacks were initially blamed on atherothrombosis, especially in women, where SCAD was the cause nearly six times as frequently. If heart attack causes are misdiagnosed, then doctors might take the wrong approach to trying to prevent the next one.
“Our research highlights the larger need to rethink how we approach heart attacks in this patient population, and for younger adult women, in particular,” said cardiologist Rajiv Gulati.
“Clinicians must sharpen their awareness of conditions like SCAD, embolism and stress-related triggers, and patients should advocate for answers when something doesn’t feel right.”
This study didn’t explore the significant difference here between men and women, but it could be the result of heart attack risk factors affecting women differently, or women being less likely to seek medical help.
That’s something that future research can look into, as well as using the same analysis techniques across larger and more diverse groups of people.
The researchers now want to see more done to raise awareness of the alternative causes behind heart attacks, both with health professionals and the public.
“Understanding why a heart attack happened is just as important as treating it,” noted Raphael. “It can mean the difference between recovery and recurrence.”
The research has been published in the Journal of the American College of Cardiology.
Study details
Causes of Myocardial Infarction in Younger Patients: Troponin-Elevation in Persons ≤65 Years Old in Olmsted County
Claire Raphael, Yader Sandoval, Joel Beachey et al.
Published in Journal of the American College of Cardiology (JACC) on 15 September 2025
Abstract
Background
The burden and pathophysiologic mechanisms of myocardial infarction (MI) in younger patients remain understudied. Prior studies have been limited by selected cohorts and lack of awareness of non-atherothrombotic causes.
Objectives
We sought to determine the incidence and outcomes of MI according to a unique pathophysiologic mechanism in a large community cohort aged ≤65 years, and to evaluate sex-differences in etiology
Methods
We identified all residents of Olmsted County, Minnesota, USA, age ≤65 who experienced an event associated with a cardiac troponin T >99th percentile of upper reference range (≥0.01 ng/mL) from January 2003 to March 2018. Records and imaging were individually scrutinised. Patients classified as MI were assigned to 1 of 6 adjudicated pathophysiologic mechanisms: atherothrombosis, spontaneous coronary artery dissection (SCAD), embolism, vasospasm, myocardial infarction with non-obstructed coronary arteries not meeting another category (MINOCA-U), and supply/demand mismatch secondary myocardial infarction. We determined incidence and long-term all-cause and cardiovascular mortality for each group.
Results
There were 4 116 myocardial injury events in 2 780 patients (36% women) over 15 years. Excluding periprocedural MI, 1 474 events were classified as index MI, of which 68% were caused by atherothrombosis. The population incidence of MI was much lower in women, particularly in MI caused by atherothrombosis (48 vs 137 per 100 000 person years and 23 vs 105 per 100 000 person-years). Incidence of SCAD was much higher in women (3.2 vs 0.9 per 100 000 person-years) with 55% of cases misclassified as MINOCA or atherothrombosis at index presentation. Women with atherothrombosis were similar in age to men (55 ± 8 years vs 54 ± 8 years), with similar disease extent at angiography but greater burden of risk factors. Proportionately, non-atherothrombotic causes comprised the majority of MI in women (atherothrombosis 47% vs 75%, secondary myocardial infarction [SSDM] 34% vs 19%, SCAD 11% vs 0.7%, embolism 2% vs 2%, vasospasm 3% vs 1%, MINOCA-U 3% vs 2%). The 5-year all-cause mortality was highest after SSDM (SSDM 33%, atherothrombosis 8%, embolism 8%, SCAD 0%) with low cardiovascular mortality in all groups.
Conclusions
This community-based study demonstrates non-atherothrombotic causes comprise an important burden of acute MI in persons age ≤65, particularly women. These cause-specific findings have implications for individualised management and risk stratification and provide epidemiologic benchmarking for future studies.
See more from MedicalBrief archives:
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Women dying from heart attacks because of failure to recognise symptoms
Women’s reproductive history linked to CVD risk – UK-Yale study