Heart attack patients receiving an inexpensive drug called metoprolol, while on the way to the hospital, may have significantly less damage in their hearts, according to clinical trial study results published Tuesday in the US journal Circulation.

The study, involving emergency ambulances and seven hospitals in Spain, showed this simple, low-cost intervention strategy with metoprolol "could be easily extended throughout the world, to provide significant clinical benefit and could change current treatment practice for heart attack patients."

Currently, patients receive no medication before undergoing routine angioplasty, the standard treatment for removing a heart blockage that causes a heart attack and damages heart tissue.

Metoprolol, a drug of the beta-blocker family, has been available for more than 30 years to treat arterial hypertension and other cardiovascular conditions. It costs less than three dollars.

In this new study, researchers from the Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) in Spain and Icahn School of Medicine at Mount Sinai in the United States examined the potential usefulness of metoprolol in heart attack patients undergoing standard angioplasty treatment procedures.

A total of 270 patients with infarction were recruited in Spain and were assigned to receive either intravenous metoprolol or a placebo treatment at the moment of diagnosis of a myocardial infarction during ambulance transit to the hospital.

The efficacy of the medical intervention was evaluated a week after the infarction by magnetic resonance imaging, which measures the mass of damaged heart tissue.

The researchers found that patients who received metoprolol had much smaller infarcts than those who received the control treatment, and that this smaller infarct size was linked to greater heart contractility.

According to the researchers, the potential savings from the treatment may go far beyond the low cost of metoprolol itself, because patients with less-extensively damaged heart muscle are less likely to need fitting with an implantable defibrillator or to require costly hospitalization for treatment of heart failure.

"The savings in healthcare costs will run into millions; a per- patient outlay of less than two euros (or less than three dollars) will over the years save thousands," co-author Borja Ibanez, head of the Experimental Cardiology Group at the CNIC, said in a statement.

Currently, the researchers are carrying out a cost- effectiveness analysis to give a firm estimate of the expected savings.

In an editorial accompanying the published article, experts from the Technische Universitat and the Munich Heart Alliance said that, if confirmed by a subsequent analysis of large numbers of patients, the results are likely to lead to a change in clinical practice.

"In this regard, a pharmaco-protective strategy able to reduce infarct size by 20 percent when used in conjunction with primary PCI (percutaneous coronary intervention) nurtures great hope in clinical benefit," the editorial said.