Can a respiratory infection increase the risk of a heart attack?

Recent findings published in Internal Medicine Journal suggest that a respiratory infection could significantly increase the short-term risk of a myocardial infarction. These studies may lead to the development of strategies that aim to lower this risk, particularly in those with increased susceptibility to such infection.

Senior author of the study, Geoffrey Tofler (University of Sydney, Australia), commented on these results: “Our findings confirm what has been suggested in prior studies that a respiratory infection can act as a trigger for a heart attack.”

The study was conducted by researchers at the University of Sydney who aimed to investigate the association between angiographically confirmed myocardial infarction and respiratory infection.

578 patients hospitalized with myocardial infarction were interviewed to assess any possible exposure to respiratory infection prior to the heart attack.

These patients were considered affected by respiratory infection if they reported a sore throat, fever, cough,  sinus pain, flu-like symptoms, and also if they had been diagnosed with either pneumonia or bronchitis.

In this assessment, 17% and 21% of patients reported such respiratory symptoms within 7 and 31 days of the heart attack, respectively.

Those that reported only upper respiratory tract infection symptoms were also then subjected to a second analysis.

Lead author Lorcan Ruane (University of Sydney) commented on the results from this second analysis: “For those participants who reported milder upper respiratory tract infection symptoms the risk increase was less, but was still elevated by 13-fold.”

“Although upper respiratory infections are less severe, they are far more common than lower respiratory tract symptoms. Therefore it is important to understand their relationship to the risk of heart attacks, particularly as we are coming into winter in Australia.”

“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,” stated 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.”

Researchers indicate that the next step now is to develop treatments to lower this increased risk of a heart attack, particularly in those that are more susceptible to such risks.

Sources: Ruane L, Buckley T, Hoo SY, et al. Triggering of acute myocardial infarction by respiratory infection. Intern. Med. J. 47 (5), 522-529 (2017);


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