| You
are getting sign out from your colleagues about your patients over
the week end. One of your patients, Mr. X who is an elderly male
being treated for pneumonia apparently went into atrial fibrillation/flutter
over the week end. He has never had atrial fibrillation or flutter
in the past, he was not hemodynamically compromised, and his heart
rate was also well controlled as he was already on a beta blocker
for Hypertension. Due to his age (73), history of Hypertension and
DM it was decided to anticoagulate him for the risk of stroke. After
finishing your sign out, you take a look at the EKG and a rhythm
strip that was recorded at the time he went into this new rhythm.
What is your interpretation of the 12 lead and rhythm strip and
do you agree with the therapeutic plan?
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This
patient does have an irregularly irregular rhythm on the 12 lead
EKG. However, what is striking in the 12 lead is lead v1. V1 shows
a very clear, organized and regular atrial activity at a rate of
270's. The rhythm strip of v1 further demonstrates this regular,
organized atrial activity at a rate of 270's. At first instinct,
one would want to call this rhythm atrial flutter, but there is
some differences between this rhythm and atrial flutter which clearly
make this a separate entity called atrial tachycardia.
First
the rate is slower that 300. Typically atrial flutter has a atrial
rate of 300. FLutter can sometimes be slower or faster, but typically
would be 300. What is more important than the rate, is the clear
iso-electric point between each p wave which is not typically seen
in flutter. Compare Figure 1 to Figure 2.
Figure 1
Figure 2
|
Figure
1 is taken from the rhythm strip in this case and Figure
two is from a case of Atrial flutter with variable bloc.
Notice in figure 2 that you have the typical saw tooth pattern
with no clear iso-electric point between the flutter waves.
In figure 1 you can clearly see the tracing returning to
baseline after every p wave.
This
was the defining characteristic which makes the EKG and
Rhythm strip on our patient represent atrial tachycardia
and not atrial fibrillation.
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The other important
finding to pick up on is the variability of the AV nodal block making
the rhythm irregularly irregular further making it seem like atrial
flutter and fibrillation. In the v1 rhythm strip you can clearly
see the different P-R intervals. At the same time the ventricular
rate is to fast to assume this is complete heart block. So therefore
this is Atrial tachycardia with variable block.
Finally, the
reason why it is important to differentiate between atrial tachycardia
and atrial flutter is because the treatment of flutter is similar
to fibrillation which involves rate control and anticoagulation
to prevent embolic events from occurring. In atrial tachycardia,
NO ANTICOAGULATION is necessary, hence alleviating the risk of bleeding
from heparin and coumadin. So in this case, the heparin should be
stopped as anticoagulation is not necessary.
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Case #43