By Dr. Victoria Shin, Cardiologist
'Tis the season...the flu season, that is. We think of the flu as a
really bad cold that knocks you out of commission for a few days with
fevers, chills and muscle aches and maybe some respiratory symptoms. In
those who are relatively healthy and lucky, that may be all they suffer.
However for those with heart disease, the flu can be deadly. For those
who have underlying heart failure or arrhythmias or coronary disease,
an influenza infection can exacerbate these underlying conditions -- resulting
in hospitalizations for heart attacks, heart failure, and arrhythmias.
A flu infection does this by increasing the stress on the heart -- increasing
heart rate, blood pressure and increasing intrinsic stress hormones called
catecholamines. It's a considerable "stress test" on the
heart, and for those who have little reserve, they may not be able to
In addition, a flu infection causes an inflammatory state in the body,
which can also trigger heart attacks by plaque rupture, as this mechanism
of heart attacks is associated with inflammation.
Even in young, healthy patients without underlying cardiovascular disease,
the flu can be deadly. The virus can affect the heart muscle resulting
in myocarditis (inflammation of the heart muscle) which can result in
severe heart failure where the heart muscle becomes so weak, it is unable
to pump on its own without requiring medications or mechanical support,
sometimes even requiring heart transplant. Since no viruses have been
isolated from autopsy specimens, we surmise that the pathology is the
body's RESPONSE TO THE VIRUS rather than the virus attacking the heart
muscle itself. Some patients can recover their heart muscle function,
but in some it can be fatal.
Same with pericarditis -- which is inflammation of the lining of the heart.
This can result in chest pain with deep breathing (because the lining
of the heart is inflammed, when you breath, they rub against each other,
causing pain). It can also cause build up of fluid in the sac surrounding
the heart -- pericardial effusion. Without prompt treatment (drainage
of the fluid) this can result in death from cardiac tamponade.
In less severe cases, myocarditis or pericarditis can mimic a heart attack
with chest pain, shortness of breath and arrhythmias. This can require
a long hospital stay for IV medications and monitoring.
As a cardiologist and a health care provider, I get the flu shot every
year. I recommend all of my patients to get it as well. Unless you can
find a good reason NOT to get it (and fear of needles should not be a
good reason), everyone should be vaccinated. It does not mean we will
prevent every single case of the flu, but it certainly decreases the chances
considerably in our favor.