- Now, on an ECG, atrial flutter
resembles sawtooth like F-waves.
This is the result of an ectopic atrial pacemaker
or because of a rapid reentry pathway somewhere
within the atria, albeit outside of the SA node area.
The origin of this ectopic pacemaker
is usually somewhere in the lower atrium
and closer to the AV node
thereby resulting in a distinct wave pattern.
Due to this erratic electrical activity,
the normal function of the SA node
is usually suppressed and non effective.
So, instead of a P-wave, atrial flutter produces flutter,
or, F-waves, as a result of the depolarization
of the atria in an abnormal manner.
The classic F-waves of atrial flutter resemble a sawtooth,
hence why we give it that name.
Now let's take a little closer look at the ECG.
First, we ask ourselves about the rhythm.
Is the rhythm regular or irregular?
In this case, it's variable,
depending on the ratio of F-waves to the QRS complex.
Then we ask ourselves, what is the rate?
The rate is variable.
Is the rate normal, fast, or slow?
In this case, the rate is variable
because of its irregularity.
So next, we evaluate the P-wave.
Are they present?
Are there anything closely resembling a P-wave
or is it just that sawtooth type F-wave?
Other P-wave questions do not apply
when we see the F-wave flutter.
Then we ask ourselves is the PR-Interval normal,
less than 0.20 seconds?
In this case, no, because it's variable.
And there are no P-waves.
So now we move on the QRS complex of the ECG.
Is the QRS interval less than 0.09 seconds?
The answer is yes.
The QRS is within normal range.
Then we ask is the QRS wide or narrow?
And in this case, the QRS is narrow.
Are the QRS complexes similar in appearance?
And we can see that each one looks similar.
So now, what is our cardiac interpretation?
Structural heart disease
is the usual cause of atrial flutter.
It can develop in newborn infants with normal hearts
and in children with congenital heart disease,
especially after cardiac surgery.
In the same way that atrial fibrillation
complicates adequate ventricular preload filling,
atrial flutter complicates circulation
especially when accompanied by a syndrome called
rapid ventricular response.
The faster the ventricular response,
the more the circulation will be compromised.