When you see a dentist why do you have to take antibiotics if you have an irregular heartbeat?

and what are the consequences if you do not take them?

So there is no chance of infection getting to your heart. Sometimes teeth are abscessed, that's why they give you antibiotics before they pull it, so the poison won't go in your system. So I would take them if I were you.

You take antibiotics for that and other conditions, particularly heart related, to prevent the germs and stuff released into bloodstream at time of dental work from hurting the heart more than it already does.

The consequences can be lethal, or serious illness. Shouldn't chance it. If you can afford to get the dental work done right, then you can afford to take the antibiotics.

This is called prophylaxis. Basically, it is warding off potential infections. your mouth is haven for bacteria. With any dental work in your mouth - which is also very vascular (meaning has lots of blood vessels), there is a risk that some of the bacteria in your mouth can get into the bloodstream and go to the heart. Some irregular heartbeats are due to valve problems (valves in between the chambers of the heart). The bacteria for some reason like to go there. So, you take antibiotics before any invasive dental procedures.

Hope this answers your query.

Oops - forgot the consequences part - bacterial endocarditis - a bacterial infection in the heart. NOT good, potentially lethal BUT treatable. You can be very ill with this condition and will definitely feel LIKE CRAP!

It is not the irregular heartbeat that requires prophylactic antibiotics; it is most likely the fact that the irregular heartbeat is caused by a heart murmur.

People with heart murmurs (small holes between chambers) are more susceptible to complications that result from skin borne bacteria.

If you have just irregular heart beats and no other heart condition, you DO NOT require antibiotics before dental work up. but,
if you also have some sort of valvular heart disease / heart murmuer, than you need antibiotics before dental work up. Dental procedures usually sheds anerobic bacterias from your mouth into the blood streem, and defective valve or valve with murmur is usually the best choosen place to settle down for bacteria , causing 'bacterial endocarditis' ( infection of valves ). so, by giving antibiotics, we kills those bacterias who gets entry into blood, before they settle down.
if you have valvular disease, you have high chance that you gets irregular heart beats. so, check it out with doc. ! it does make a difference in decision about antibiotics. !
( usually, an 2D-Echo is sufficient to know about that. ).

to avoid infection