ANAHEIM, Calif. -- Getting an annual influenza shot may do more than represent a shot in the arm to preventing the flu. It might also reduce heart attacks.

A new study suggests that heart patients may significantly reduce their risk of a second heart attack if they get vaccinated against influenza.The finding is still considered preliminary and needs to be confirmed by further studies. Still, doctors say it raises the possibility of a powerful and underused way of keeping the heart healthy.

The study, directed by Dr. Morteza Naghavi of the University of Texas, supports the theory that a variety of infections can inflame the buildups that clog the arteries, making them more likely to break open and trigger heart attacks.

Naghavi based his study on 233 patients who were treated between October 1997 and March 1998. He presented the results at a meeting of the American College of Cardiology.

At the same meeting, two other studies were released showing that heart attacks tend to be more severe during the cold months, and cardiac arrest is most common in the winter.

Naghavi's study compared people who suffered second heart attacks with those who did not. Those who had flu shots reduced their risk of new heart attacks by 67 percent.

If flu shots truly do protect heart patients, he said, "educating this population and physicians could help increase the rate of vaccination, which is still under 65 percent."

On the Net: American College of Cardiology site: