Flu virus critical for heart patients: Study

A research team led by Andrew C. Hayward, a senior lecturer in infectious disease epidemiology at the UCL Centre for Infectious Disease Epidemiology in London, analyzed 39 studies conducted between 1932 and 2008 in order to determine the risk of heart attack among those infected with flu.

The researchers found that there was an increase in deaths due to heart attacks during the flu season by an average rate of 35 to 50 percent. However, the studies showed that the risk of dying from heart attack or suffering from the same was reduced on getting a flu shot.

The team said that influenza vaccination should be encouraged among people who suffer from cardiovascular diseases.

"We believe influenza vaccination should be encouraged wherever indicated, especially in those people with existing cardiovascular disease. Further evidence is needed on the effectiveness of influenza vaccines to reduce the risk of cardiac events in people without established vascular disease," the researchers concluded.

Flu viruses detrimental to heart’s health
Experts say that flu viruses can worsen existing medical conditions as they cause inflammation in the body, usually in the lungs.

But they can also cause swelling in the heart or in the coronary arteries, which could lead to dangerous clots breaking off and lodging in the heart, causing a heart attack. Also, the heart patients infected with flu are more prone to severe medical conditions like pneumonia and other infections.

It has not been ascertained yet whether the study results also apply to otherwise healthy people with no history of cardiovascular problems. But if such people are obese or have risk factors like high blood pressure or high levels of cholesterol, then flu viruses could potentially trigger heart attacks in them.

Dr. Marc Siegel, an associate professor of medicine at New York University School of Medicine in New York City said, "Influenza is most concerning because of its secondary complications. Most of the time with influenza, death or hospitalization isn't because of the influenza, it's because influenza puts you in a weakened state -- it's a stress on the system.

"So, it is not surprising that you would have the increased risk of a myocardial infarction during or right after an influenza infection.”

Heart patients should get vaccinated
In the wake of global outbreak of swine flu, doctors advise heart patients to get vaccinated against both regular flu and swine flu to avoid medical problems. More flu viruses will be circulating this year, it is learnt.

Previous studies have also revealed that more cardiovascular events occur in patients with influenza whereas individuals who receive annual flu shots are much less likely to have cardiovascular problems.

Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles said, "Guidelines from the American Heart Association and American College of Cardiology strongly recommend that all individuals with cardiovascular disease receive annual influenza vaccination.”

The study appears online in the British medical journal, The Lancet Infectious Diseases.