Mayo Clinic Sep 15 2025 A new Mayo Clinic study finds that many heart attacks in people under 65 - especially women - are caused by factors other than clogged arteries, challenging long-standing assumptions about how heart attacks occur in younger populations. Study findings published in the Journal of the American College of Cardiology examined over 15 years of data from the Rochester Epidemiology Project, providing the most comprehensive population evaluation of heart attack causes in people