A large autopsy study from San Francisco has upended a long-held belief in cardiology: heart attacks are not the leading cause of sudden cardiac death. Researchers found that only 41% of confirmed sudden cardiac deaths were due to heart attacks — roughly half the previously accepted 80% figure. The remaining deaths stemmed from conditions like hypertensive heart disease, dilated cardiomyopathy, and substance-related heart disease. A companion study found that two-thirds of arrhythmic sudden cardiac deaths occurred in people with no previously diagnosed cardiac risk factors, yet half showed hidden signs of heart disease detectable in principle. These findings suggest current cardiac screening is missing high-risk individuals and that prevention efforts need to broaden well beyond coronary artery disease.
