(HealthDay News) -- From city to city, there is a more than fivefold difference in the odds that someone will survive sudden cardiac arrest, with the chances resting on whatever emergency response system is in place, a new study finds.

MONDAY, Sept. 15 (HealthDay News) -- Human stem cells derived from bone marrow can cut the brain damage caused by an interruption in blood supply, such as what happens after a heart attack, scientists report.

Although these initial results were seen in mice, researchers are hopeful the breakthrough will one day help humans struck by cardiac arrest or stroke.

WEDNESDAY, July 9 (HealthDay News) -- Compared to CPR alone, adding extracorporeal life support doubles survival in hospital patients with cardiac arrest, says a study by researchers at the National Taiwan University Hospital.

Exciting news!

Dr. John T. McDevitt, a biochemist at the University of Texas at Austin, along with colleagues, has developed a saliva test that can determine whether a person has had a heart attack. This test can be administered anywhere, even in an ambulance on the way to the hospital, lessening the need to begin tests at a later time, and allowing cardiac care to begin much earlier.

It is the protein in the saliva that can determine a heart attack and once the saliva is placed in a lab card, it takes 15 minutes for analysis.

WEDNESDAY, April 16 (HealthDay News) -- Your chances for surviving a cardiac arrest are 13.4 percent worse if you are admitted to the hospital on the weekend versus a weekday, according to new research.

(LifeWire) -- Forty-five-year-old Mary Pakusch doesn't remember what happened in the minutes and hours after she went into sudden cardiac arrest at home on July 15, 2006. Her husband Paul does. Mostly, he remembers how scared he was. "She was living a perfectly normal life," says Paul, 47, who works at a Rochester, New York, television station.

TUESDAY, March 11 (HealthDay News) -- Cardiac arrest outside of the hospital can quickly turn deadly, but a new method of restarting stalled hearts might boost people's chances of survival, researchers say.