Sudden Cardiac Arrest Is Preceded By Warning Signs In Just Over Half Of All Cases

Sudden cardiac arrest doesn't always have to come unexpectedly. A new study found that over half of victims experienced symptoms prior to their episode, according to the American Heart Association's (AHA) blog.

Sudden cardiac arrest is the "abrupt loss of heart function in someone who may or may not have heart disease," and it "occurs instantly or shortly after the first symptoms appear," according to the AHA. In essence, the heart's electrical system fails, a scenario played out in around 360,000 people outside the hospital each year. The in-hospital versus out-of-hospital distinction is important because of how quickly the phenomenon strikes; just 9.5 percent of all those who experience cardiac arrest outside the hospital survive, according to AHA. Saving a life typically requires immediate CPR.

"By the time rescuers get there, it's much too late," said Eloi Marijon, M.D., the study's lead author and a visiting scientist at Cedars-Sinai Heart Institute in Los Angeles.

Marijon's research, part of the Oregon Sudden Unexected Death Study (which also involves the Center for Disease Control), tracked 567 middle-aged men in Portland, Oregon who experienced out-of-hospital cardiac arrest and found that 53 percent had symptoms a month before their cardiac episodes. Of that group, 56 percent experienced chest pain, 13 percent experienced shortness of breath and 4 percent experienced dizziness, fainting or palpitations, according to AHA.

The symptoms typically occurred (80 percent of the time) between four weeks and an hour before cardiac arrest, according to the AHA. Though most of the men had coronary heart disease, only half had been tested and were aware of their condition.

"The lesson is, if you have these kinds of symptoms, please don't blow them off," said Sumeet Chugh, M.D., associate director for genomic cardiology at the Cedars-Sinai Heart Institute. "Go see your healthcare provider. Don't waste time."

Cardiac arrest is different than a heart attack, though the latter can lead to the former, according to the AHA. A heart attack is the result of a blockage that impedes blood flow to the heart and results in the death of muscle tissue surrounding the heart. Cardiac arrest compromises the whole system and is typically more deadly.