TUESDAY, March 27 (HealthDay News) -- Training paramedics to give probable heart attack patients a mixture of glucose, insulin and potassium may lessen the severity of a heart attack and save lives, new research suggests.

When someone suspects a heart attack and dials 911, the responding paramedics will quickly assess whether or not the person is in the throes of having a heart attack, or about to have one. Typically, paramedics will give aspirin to thin the blood and nitroglycerin for chest pain while transporting the patient to the hospital.

But the new study indicates that if paramedics administer the glucose/insulin/potassium solution right away, they can reduce the risk of cardiac arrest (when the heart suddenly stops beating) and death by 50 percent. This potentially lifesaving cocktail is readily available and costs just $50, the researchers noted.

"It can't stop a heart attack, but it can make it smaller and reduce the risk of cardiac arrest and death," said study author Dr. Harry P. Selker, executive director of the Institute for Clinical Research and Health Policy Studies at Tufts Medical Center in Boston.

The findings were to be presented Tuesday at the American College of Cardiology annual meeting in Chicago, and published online simultaneously in the Journal of the American Medical Association.

The cardiac cocktail basically feeds the heart during a time when it would be starved of oxygen and nutrients, and keeps levels of dangerous free fatty acids in check, Selker explained.

Until now, the treatment had not been administered early enough in the course of a heart attack to make a difference in outcomes. But, "we did it in people's homes and while driving to the hospital," Selker said. And it worked.

In the trial, paramedics from 13 cities were trained to administer the solution after determining that an individual was likely having or about to have a heart attack. Overall, 911 people received either the solution or a placebo. People who received the solution immediately after being diagnosed with acute coronary syndrome -- which means a heart attack is in progress or imminent -- were 50 percent less likely to experience cardiac arrest or die compared to those who received the placebo. The results were even more pronounced for people with more severe ST-elevation heart attacks ( a pattern assessed via electrocardiogram). Among this group, immediate treatment with the solution resulted in a 60 percent reduction in risk for cardiac arrest or death.

The treatment did not prevent the heart attack from occurring, but may have lessened the damage that it caused. On average, 2 percent of the heart tissue was destroyed by the heart attack in people receiving the solution, compared with 10 percent in those who received the placebo.

Twenty-three percent of heart attacks in the study were later determined to be false alarms. This rate is lower than what is typically seen. In the study, paramedics used decision support tools to make the call. Administering the solution does not appear to cause any harm in people who are not having a heart attack, the authors said.

The researchers are following up with study participants at six and 12 months to see how they have fared in the longer term. "Larger trials should be done, but this therapy is inexpensive and can be used everywhere," Selker said.

Dr. Robert Glatter, an emergency medicine physician at Lenox Hill Hospital in New York City, expressed some caution. "This is very preliminary," he said. "This therapy has been around since the 1960s and never proved to be effective, so we must be very cautious in interpreting the new findings."

The solution is indeed inexpensive and widely applicable, but potential risks include infusion-related hyperglycemia (elevated blood sugar), hyperkalemia (elevated potassium) and fluid retention, he said.

More information

Learn more about heart attack risks at the U.S. National Heart, Lung, and Blood Institute.