NEW YORK, Sept 16: A new study from Mayo Clinic has found that many heart attacks in adults under the age of 65 — particularly women — are caused by factors other than clogged arteries, challenging long-standing assumptions about the origins of heart attacks in younger populations.

Published in the Journal of the American College of Cardiology, the research analyzed over 15 years of data from the Rochester Epidemiology Project, making it the most comprehensive population-based evaluation to date of heart attack causes in individuals aged 65 and under.

Key findings showed that more than half of heart attacks in women under 65 were due to nontraditional causes, such as spontaneous coronary artery dissection (SCAD), embolism, or other mechanisms unrelated to artery-clogging plaque, also known as atherosclerosis.

While atherosclerosis remained the most common cause of heart attacks overall, it accounted for only 47% of cases in women, compared to 75% in men. Additionally, SCAD — a condition that predominantly affects younger, otherwise healthy women — was nearly six times more common in women than in men, but frequently misdiagnosed as plaque-related heart attacks.

“This research shines a spotlight on heart attack causes that have historically been under-recognized, particularly in women,” said Dr. Claire Raphael, M.B.B.S., Ph.D., an interventional cardiologist at Mayo Clinic and first author of the study. “When the root cause of a heart attack is misunderstood, it can lead to treatments that are less effective — or even harmful.”

In some cases, misdiagnosed SCAD patients received stents unnecessarily, potentially raising their risk of complications. The study emphasizes that correct diagnosis of nontraditional causes leads to better treatment decisions and improved long-term outcomes.

Another significant finding was that heart attacks triggered by stress-related factors — such as anemia or infection — had the highest five-year mortality rate, reaching 33%, despite patients typically showing lower levels of heart damage. These stress-related events were the second most common overall cause.

Out of 1,474 heart attack cases reviewed, the study found:

“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 Dr. Rajiv Gulati, M.D., Ph.D., chair of the Division of Interventional Cardiology and Ischemic Heart Disease at Mayo Clinic and senior author of the study. “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.”

Dr. Raphael added, “Understanding why a heart attack happened is just as important as treating it. It can mean the difference between recovery and recurrence.”

The study’s findings are expected to prompt a shift in how heart attacks in younger adults — especially women — are diagnosed and managed, potentially improving outcomes through more targeted and appropriate care.