Heart attack sufferers who are left with very low ejection fractions - a sign that the heart is not pumping efficiently - appear to benefit from a novel procedure in which the patient’s own stem-like “progenitor” cells are infused into the heart.

In a study reported Sunday at the annual meeting of the American Heart Association, heart attack survivors infused with these enriched cells derived from their own bone marrow had nearly twice the improvement in their heart’s pumping ability as patients given a placebo infusion.

The benefits seen at four months after a heart attack appeared to be most evident in patients with large heart attacks, those that produced the greatest damage to the heart muscle.

“Progenitor cell therapy after a heart attack is a new therapeutic strategy that completely differs from all the therapeutic options we have so far,” Dr. Andreas M. Zeiher, from J. W. Goethe University in Frankfurt and senior author of the study said in an AHA statement.

Existing therapies, the researcher explained, only limit further damage to the heart, whereas progenitor therapy has the potential not only to limit damage but also to regenerate heart function.

The study involved a total of 204 heart attack patients at 17 medical centers who were randomly assigned to infusions into their hearts of progenitor bone marrow cells or placebo.

At the start of the study, ejection fractions were virtually the same in both groups - 47 percent in the placebo group and 48 percent in the active treatment group.

At four months, both groups had improved, as expected. The overall increase in ejection fraction was 5.5 percent in progenitor cell recipients versus 3.0 percent in placebo patients.

The beneficial effects of progenitor cell infusion therapy were especially marked in those with lower ejection fractions. These subjects enjoyed a three-fold increase in ejection fraction compared with placebo.

Other findings were equally encouraging, the authors say, noting that progenitor cell therapy patients had less heart enlargement compared to placebo patients. Heart enlargement is part of the post-heart attack remodeling process where the heart tries to compensate for reduced pumping action. An enlarged heart is incapable of pumping efficiently and the condition is often seen in cases of heart failure.

Patients receiving progenitor cell therapy also showed improved blood flow in the artery where the heart attack occurred, suggesting that new blood vessels were created to nourish the damaged area of the heart.