Let’s talk for a few
minutes about arrhythmias.
This is a huge field, actually, a total specialty
on to itself and in a few minutes here, I am
not going to be able to do anything more than
brush the surface, but I am going to talk
about the most common arrhythmia which is
atrial fibrillation. Mention… I mentioned
it just previously, right? The heart, as you
know, has electrical system as we have talked
about which keeps it beating very regularly
like this, the im-… electrical impulse starts,
remember in the high right atrium, and passes
through the atria and down into the ventricle
causing a co-ordinated contraction. What happens
though when that electrical activity is disturbed
in the atria and instead of doing this, the
atria do this? When that happens, of course,
we get areas of low blood flow within the
atria and as I have mentioned before, a clot
can form and that clot can result in a stroke,
if the clot gets outside the heart.
So, first of all, we have drugs actually for
trying to control atrial fibrillation and
keeping patients in sinus rhythm. There’s
a whole variety of these drugs, but many of
them are associated with very significant
side effects. When I talked about Statins,
remember I mentioned very few side effects.
But, when I am talking now about anti-arrhythmic
drugs, the number of side effects is quite
severe and even some of the side effects can
So, these agents have to be used very carefully,
just like the powerful anti-coagulants. You
have to use them carefully. It requires a
great deal of training to use these drugs
effectively and also, to pick the right patient
to get them.
So… and remember what I also said, one of
the other treatments in a patient with atrial
fibrillation is to prevent the blood clots
and prevent the stroke. So, sometimes, we
will give drugs that hold the patients in
sinus rhythm and sometimes, we can do an electrical
procedure where we sort of… with a catheter
burn out the area that’s setting off the
atrial fibrillation. Often, that means you
still have to take some anti-arrhythmic drugs
and a blood thinner to prevent the blood clots.
So, the treatment of… of patients with atrial
fibrillation often involves several drugs.
Both a drug to either control the heart rate
and leave the patient in atrial fibrillation
or control the atrial fibrillation and restore
the patient to the regular sinus rhythm. And
finally, there are agents to prevent the blood
clots within the heart.
I just want to show you two examples, again.
Here, you will recognize this as an electrocardiogram.
This is a normal electrocardiogram. I am
not going to spend any more time going over
all the details of it other than to say, it
shows the patient in nice regular rhythm.
And you can see that nice, regular rhythm,
each heart beat which is the big upward and
downward deflection comes at approximately
the same time.
Compare this normal electrocardiogram with
this electrocardiogram in atrial fibrillation.
Notice, here the spikes are completely irregular
and the heart rate is very fast. It’s about
130. And that’s very common in atrial fibrillation.
Patients recognize it because they say, “Oh
my goodness! All of a sudden my heart is racing
away with me.” And if you try and take the
pulse, let’s do a little… sound experiment.
In sinus rhythm, the pulse goes like this
“boom, boom, boom, boom”. In atrial fibrillation,
the pulse goes like this, “boom, booboom,
boom, booboom, booboom, booboom, boom”.
You can hear, it’s first of all, very fast
and second of all, very irregular.
If patients have underlying heart disease,
you could imagine that this fast heart rate
is not good. If the patient has narrowings
in the coronary arteries, the fast heart rate
can make the heart run away from its blood
supply and cause angina and even cause heart
In patients who are in heart failure, it can
make the heart failure much worse. They become
much more short of breath and very frequently,
these patients come to the emergency room
We will talk a little bit more about this
when we talk in the section on arrhythmias
later in ths series of lectures. In any
case, it’s important for you to remember
that atrial fibrillation is the commonest
arrhythmia that we see. It becomes increasingly
common with age and occurs in about 10% of
people over the age of 80, both in Western
Europe and in the Unites States. So, very,
very common problem.
There are other approaches, as I mentioned,
besides drugs, to arrhythmia control. I mentioned
that there is a catheter based technique in
which one can actually burn out the focus
in the atrium that’s setting off the atrial
fibrillation. Still, the patients often have
to take drugs after that, both anti-arrhythmic
drugs and drugs to… drugs to prevent blood
Sometimes pacemakers can… special pacemakers
can be inserted that help to decrease the
risk of these arrhythmias and most of these
things are going to be combined with drugs
in order to control the arrhythmias.
In many patients, the arrhythmias are fairly
easy to control with a modest number of drugs.
In other patients, they can be very difficult
and there are multiple ablations, which is
the electrical destruction of the arrhythmia
that starts, multiple drugs used, these patients
can be very, very challenging. Fortunately,
they are the minority.
In summary then, there are a variety of drugs
that have been developed for the treatment
of cardiovascular disease. Some of these
drugs are used preventively. In other words,
to prevent patients who are at high risk from
developing heart attacks and strokes and the
same drugs can also be used once the disease
becomes manifest in preventing a second episode
of heart attack or stroke. And of course,
we are always looking for new agents to further
improve our ability to care for this very
Thank you very much. I look forward to being
with you for the next presentation.