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Exotic atrial ectopy part two

By Assoc Prof Harry Mond
/
September 14, 2020

Previously, we covered some of the ECG patterns seen with atrial ectopy.

Let us continue.

An atrial couplet is defined as two consecutive atrial ectopics:

Both ectopics are premature and from a low atrial site.

However, only one may be “obviously premature”:

Or neither:

An atrial couplet may not always be a couplet:

In this example, there may only be a single interpolated atrial ectopic, but the timing is against this. The R-R interval with the embedded ectopic should be the same or longer (due to partial refractoriness in the atrio-ventricular conducting system) than the sinus cycle length. It is significantly shorter and therefore most likely an atrial couplet.

Atrial couplets may demonstrate Wenckebach atrio-ventricular block:

Non-conducted atrial ectopics (blue dots) may also occur:

But not all non-conducted atrial couplets are actually “couplets”:

The first non-conducted beat is part of a 2:1 atrio-ventricular block sequence (red dot) and the second is an atrial ectopic (blue dot), which not surprisingly is non-conducted.

Three consecutive atrial ectopics an atrial triplet:

They too can present as a Wenckebach atrio-ventricular sequence:

Can non-conducted atrial triplets occur?

Here is an example:

Although, there are three consecutive non-conducted atrial ectopics, the cycle length is very short and mimics the appearance of atrial flutter.

More correctly, this is a short run of focal atrial tachycardia with Wenckebach block at the ectopic-myocardial junction.

Here is a sequence of nine consecutive conducted atrial ectopics. We can’t call this supraventricular or atrial tachycardia, because the rate is <100 bpm.

My technicians call this an atrial run and it is a very common finding on Holter monitoring.

Not surprisingly atrial runs (red highlight) can occur together with supraventricular tachycardia (yellow highlight).

Remember, it’s all in the timing

Harry Mond

About Assoc Prof Harry Mond

In 49+ years as a practicing cardiologist, Assoc Prof Harry Mond has published 260+ published manuscripts & books. A co-founder of Cardiac Monitoring Service, he remains Medical Director and oversees 500K+ heart studies each year.

Download his full profile here.

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