Family doctor

A study published in the New England Journal of Medicine has found that people with confirmed influenza infection are 6 times more likely to have a heart attack within 7 days of their infection, compared with the period before and after that.

This risk was particularly strong in those over 65 years old. While the influenza B virus had the strongest link to heart attacks, other respiratory viruses such as RSV (respiratory syncytial virus) were also shown to put people at an increased risk.

The study supports a large body of evidence suggesting that there is a relationship between respiratory viral illness and heart attacks, but this is the first study to specify the exact pathogen through laboratory-confirmed testing in over 300 patients.

The study supports the recommendation that everyone who can should receive a flu vaccine, particularly those who have had previous heart attacks, and those with high risk factors for heart disease such as elevated blood pressure, diabetes, high cholesterol and smoking.

While the exact mechanism for how influenza increases the risk of heart attack is not yet known, theories include that the virus triggers inflammatory reactions that can increase the chance of plaque rupture, and that the flu increases the body’s demand for oxygen, potentially precipitating ischemia in those who already have narrowed coronary arteries.

Reference:

1. Kwong, Jeffrey C., et al. "Acute myocardial infarction after laboratory-confirmed influenza infection." New England Journal of Medicine 378.4 (2018): 345-353.