Berlin ? Giving most heart attack patients an infusion of glucose soon after they come to the hospital could dramatically improve their chances of survival, preliminary new research suggests.

The Dutch study found that supplementing regular treatment of heart attacks with the extra fuel reduced the risk of dying within a month from 4.2 percent to 1.2 percent but only for patients whose hearts had not suffered substantial damage in the attack.

Experts said the study presented Sunday at the annual meeting of the European Society of Cardiology was promising but stressed the findings were preliminary.

“The time of follow-up is probably too short to draw firm conclusions,” said Dr. Lars Ryden, a professor of cardiology at the Karolinska Institute in Stockholm, who was not involved with the research. “We are eager to know the long-term results.”

When heart muscle is damaged, the metabolism in the heart increases and the cells need a lot more glucose, their main fuel, to stay alive.

The infusion includes insulin, which is needed to transport the glucose into the cell. However, insulin also causes a flux of potassium into cells, which depletes the levels in the blood. Potassium is therefore added to the infusion to compensate for that effect.

In the 1950s and 1960s, several studies investigated the prospect of boosting fuel to the heart with infusions of glucose, insulin and potassium.

However, the evidence was inconclusive and doctors were left confused. Also, it has never been tested in combination with today’s standard therapies.

Those involve trying to get rid of the clot that caused the heart attack either by widening the arteries with instruments or dissolving the clot with drugs.

The latest study involved 940 patients treated at the De Weezenlanden Hospital in Zwolle in the Netherlands.

Half the patients also got an infusion of the high-dose glucose mixture. They got about 4.3 pints of the fluid intravenously over 10 hours.

Overall, the death rate over the next 30 days was about the same in the two groups about 5 percent.

However, the results significantly improved when restricted to the 90 percent of patients who had not suffered severe damage or heart failure.

Only 5 people who got the infusion were dead 30 days later, compared with 18 in the group who didn’t get the tonic.

“These data show that at least we should take it seriously,” said Dr. Felix Zijlstra, a cardiology professor who led the research. “Metabolic intervention seems to have a future on top of other therapy and provided they don’t have heart failure.”