Depression and heart disease may be linked by the body’s stress response, though more research is needed to say for sure. Depression can trigger feelings of stress, which raises your blood pressure and heart rate. Over time, this can damage your blood vessels and make your heart less able to adjust to your body’s needs. And, according to the American Heart Association, some studies show that up to 33 percent of people who have a heart attack or other cardiac event will develop depression. While it’s normal to feel sad, angry, or anxious after a heart attack or heart surgery, talk to your doctor if these feelings last longer than a few weeks.