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'Silent' heart attacks often undiagnosed

April 21, 2009 12:00:00 AM PDT
Each year in the United States, as many as 200,000 people may suffer a heart attack and never even know it. According to Duke University Medical School researchers, so-called "silent" heart attacks, which go unnoticed and undiagnosed, are more prevalent than was previously thought.A heart attack is caused by a clot interfering with the flow of blood from a coronary artery to the heart. Often this produces well-known symptoms such as severe chest pain, shortness of breath, fainting, and nausea. But sometimes when there is no pain, or the person experiencing the heart attack fails to recognize other symptoms as heart-related, he or she does not go to a hospital for treatment. Researchers estimate that as many as 40 t0 60 percent of all heart attacks may be of this "silent" type.

The study was conducted on 185 patients who had never been diagnosed as having a heart attack, but were suspected of having coronary artery disease. Researchers found that after two years, 35 percent of the patients showed evidence of a "silent" heart attack. Treatment for someone who has suffered an undiagnosed heart attack is usually the same as for someone who went to the hospital immediately following an attack, and can include beta blockers, statin drugs, aspirin, or other medications.

Generally speaking, health experts do not recommend that people get screened for silent heart attacks unless they have other heart-related problems. "Currently, there has not been a study that has demonstrated that early identification and therapy changes how patients with unrecognized heart attacks do in the future," said Dr. Han Kim, a cardiologist and the lead author of the study. "If you don't know when an actual event occurred, it becomes difficult to prescribe therapy."