How the Flu Affects the Heart

By: Tracy Hampton
BIDMC Correspondent
Getting the flu often just means a few days of feeling lousy, but for some, it can have dangerous effects on the heart. “In patients with pre-existing heart disease, and especially in the elderly, the flu can cause increased heart rate and overall stress. This can lead to a higher frequency of heart attacks, angina, heart failure, and subsequent hospitalizations,” says Dr. Francesca Nesta Delling, of the Beth Israel Deaconess Medical Center CardioVascular Institute. Heart disease also increases the risk of experiencing flu-related complications such as pneumonia.
The US Department of Health and Human Services advises individuals with heart disease to get the flu vaccine to help protect against getting the flu. In addition, it is better for heart disease patients to get the flu shot, not the nasal spray. If they develop flu-like symptoms, they should contact their doctor immediately. Amantadine, rimantadine, zanamivir, and oseltamivir are flu medications than can be taken by patients with underlying heart disease. Just like others, they should get plenty of rest and drink clear fluids if they get the flu.
Dr. Delling adds that in rare situations in individuals with no heart disease, inflammation of the heart muscle, which is called myocarditis, or inflammation of the sac that surrounds the heart, called pericarditis, can develop in response to an influenza infection. “Since no viruses have been found growing in the heart muscle of autopsy specimens, it is thought that myocarditis and pericarditis are secondary to the body’s response to the virus more than a direct effect of the virus on the heart,” explains Dr. Delling. Also, on occasion, the pericarditis can cause a buildup of fluid around the heart that can in turn impair the filling of the heart chamber.
Interestingly, two studies found that the influenza vaccine may reduce cardiovascular events—like strokes and heart attacks—and cardiovascular death in people with or without heart disease. The reason for the link is unclear, but it may relate to how the vaccine strengthens the immune system. Currently, less than 40% of US adults get the flu vaccine each year.
Above content provided by Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.