Respiratory infection increases heart attack risk

Suffering a respiratory infection increases the risk of having a heart attack during the following week significantly, according to Australian research.

The researchers at the University of Sydney say they are the first to find an association between respiratory infections and increased risk of heart attack in patients using coronary angiography.

Professor Geoffrey Tofler, cardiologist from University of Sydney, Royal North Shore Hospital and Heart Research Australia, said its study confirmed suggestions in previous studies that respiratory infection can lead to heart attack.

"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,” he said.

The study, which is published today in Internal Medicine Journal, investigated 578 patients who had suffered a heart attack due to a coronary artery blockage.

Of those, 17% reported symptoms of respiratory infection within seven days of the heart attack, while 21% said it was within 31 days.

Patients were considered to be affected if they reported sore throat, cough, fever, sinus pain, flu-like symptoms, or if they reported a diagnosis of pneumonia or bronchitis.

Researchers believe that the reason behind the increased risk could be an increased tendency towards blood clotting, inflammation and toxins damaging blood vessels, and changes in blood flow.

"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,” said Prof Tofler.

"The next step is to identify treatment strategies to decrease this risk of heart attack, particularly in individuals who may have increased susceptibility."

A second analysis among patients whose symptoms were in the upper respiratory tract, such as the common cold, pharyngitis, rhinitis and sinusitis also found an increase in heart attack risk of 13%.

Internal Medicine Journal 15 May 2017