Make the appointment: If you have heart disese, a flu shot could be a life saver.

RODALE NEWS, EMMAUS, PA—Worries over a swine-flu pandemic will have many people clamoring for a dose of the swine-flu vaccine when it becomes available in October. But, for people with heart disease, the regular seasonal flu may be more of an issue. "It has been known for many years that [seasonal] influenza can cause some cardiac complications," says Charlotte Warren-Gash, MD, Medical Research Council clinical research training fellow at the University College London Centre for Infectious Disease Epidemiology, and lead author of a review of studies published in The Lancet on a seasonal flu-heart attack link. A condition called myocarditis (inflammation of the heart wall) is known to be triggered by the flu virus, she adds. However, exactly how influenza and other complications are linked is less clear, although there does appear to be a link. "Heart-attack rates have been shown to peak at a similar time to rates of influenza circulation," she says.

THE DETAILS: In order to gather as much information as it could on a possible connection, her team searched medical databases for studies on seasonal-influenza viruses (pandemic flus like the swine flu and avian flu weren't included in the study), flu vaccinations, and heart complications, specifically heart attacks and death due to any type of heart complication. Of the 39 studies the team found on the topics, a majority of them showed consistent links between heart attacks and flu infections, although there wasn't as consistent a link between cardiac death and flu. "Influenza might trigger an inflammatory response throughout the body, including the coronary blood vessels that supply the heart," says Dr. Warren-Gash. That inflammation, she notes, could be the reason that flu viruses may trigger heart attacks.