The risk of having a heart attack is 17 times higher in the seven days after a serious respiratory infection, Australian research has found.
Previous research has suggested a bout of the flu, pneumonia or bronchitis can trigger a heart attack but a study published in in the Internal Medicine Journal has confirmed the association.
"The data showed that the increased risk of a heart attack isn't necessarily just at the beginning of respiratory symptoms, it peaks in the first seven days and gradually reduces but remains elevated for one month," said senior author Professor Geoffrey Tofler, a cardiologist from University of Sydney, Royal North Shore Hospital and Heart Research Australia.
Milder upper respiratory tract infections, such as strep throat and sinusitis, were also linked to a "13-fold" increase of heart attack.
Researchers at the University of Sydney investigated more than 550 heart attack patients.
Seventeen per cent of patients reported symptoms of respiratory infection within seven days of the heart attack, and 21 per cent within 31 days.
Symptoms included sore throat, cough, fever and sinus pain.
Possible reasons for why respiratory infection may trigger a heart attack include an increased tendency towards blood clotting, inflammation and toxins damaging blood vessels, and changes in blood flow.
With winter just weeks away, it's important the community take preventative steps to reduce a potentially life-threatening coronary event, warns Prof Tofler.
"Our message to people is while the absolute risk that any one episode will trigger a heart attack is low, they need to be aware that a respiratory infection could lead to a coronary event. So consider preventative strategies where possible, and don't ignore symptoms that could indicate a heart attack.
"The next step is to identify treatment strategies to decrease this risk of heart attack, particularly in individuals who may have increased susceptibility."
