Washington, D.C. ? Severe depression may silently break a seemingly healthy woman’s heart.

Doctors have long known that depression is common after a heart attack or stroke, and worsens those people’s outcomes. Monday, Columbia University researchers reported new evidence that depression can lead to heart disease in the first place.

The scientists tracked 63,000 women from the long-running Nurses’ Health Study between 1992 and 2004. None had signs of heart disease when the study began, but nearly 8 percent had evidence of serious depression.

The depressed women were more than twice as likely to experience sudden cardiac death — death typically caused by an irregular heartbeat, concluded the 12-year study, published Monday in the Journal of the American College of Cardiology. They also had a smaller increased risk of death from other forms of heart disease.