MONDAY, Dec. 21, 2015 (HealthDay News) -- Sudden cardiac arrest may not be as sudden as doctors have thought, researchers report.

Roughly half of cardiac arrest patients experience telltale warning signs that their heart is in danger of stopping in the month preceding their attack, new study findings suggest.

Those symptoms can include any combination of chest pain and pressure, shortness of breath, heart palpitations, and flu-like sensations (such as nausea, back pain and/or abdominal pain), the researchers said.

The problem: less than one in five of those who experience symptoms actually reach out for potentially lifesaving emergency medical assistance, the investigators found.

"Most people who have a sudden cardiac arrest will not make it out alive," warned study co-author Dr. Sumeet Chugh, associate director of the Heart Institute and director of the Heart Rhythm Center at Cedars-Sinai Medical Center in Los Angeles. "This is the ultimate heart disease, where you die within 10 minutes. And less than 10 percent actually survive," he said.

"For years we have thought that this is a very sudden process," Chugh added. "But with this study we unexpectedly found that at least half of the patients had a least some warning signs in the weeks before. And this is important, because those who react by calling their loved ones or calling 911 have a fivefold higher chance of living. So, this may open up a whole new paradigm as to how we may be able to nip this problem in the bud before a cardiac arrest even happens."

Chugh and his colleagues published their findings in the Jan. 5 issue of the Annals of Internal Medicine.

Though many people use the terms interchangeably, cardiac arrest is not the same as a heart attack. While a heart attack results from arterial blockage that cuts off blood flow to the heart, a cardiac arrest occurs when the heart's electrical activity goes awry and the heart stops working.

Upwards of half of all heart-related deaths in the United States occur as the result of cardiac arrest, killing 350,000 Americans every year, the study authors noted.