Transcript Housecalls Puzzler September 2014

ECG Underwriting
Puzzler
Presented by: William Rooney, M.D.
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QUESTION????
What is the major
abnormality
this ECG?
Week
13 in theon
“Case
of the Week” series
OK, fine. There are several abnormalities. So, how about rhythm
abnormalities?
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Analysis
Week 13 in the “Case of the Week” series
CLUE:
Look for the p waves
P waves are hard to find
huh.
How about the regularity of
the rhythm?
Irregularly irregular….what
could cause that
appearance?
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Reviewing the
Disorder
Week
13 in the “Case of the Week” series
You are right if you said
Atrial Fibrillation
The intervals are
all different
Measure the R-R interval
Notice that they have no
identifiable repetitive pattern
Don’t get confused if you
observe electrical activity in
some leads suggestive of p
waves but no distinct p
waves are found such as is
seen in V6. Baseline
artifact is common and can
be confusing.
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Animation of the disorder
Here is a diagram of the normal
conduction system of the heart
Ectopic foci
This is animation trying to depict a
normal SA node generated beat in
the atrium
SA
NODE
AV
NODE
Ectopic foci can develop anywhere
in the atrium and can compete with
the normal SA node
When multiple ectopic foci are
present it can get chaotic
This animation tries to depict atrial
fibrillation competing with the
normal SA node in the atrium
The AV node is stimulated
repeatedly from different focus. It
irregularly allows an impulse
through causing an irregularly,
irregular heart rate
Atrial fibrillation occurs when there are multiple irritable
automaticity foci in the atria
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ECG features of this disorder
Features
Features of atrial fibrillation
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No discrete P waves
F waves (fibrillatory) are present sometimes
No repetitive pattern to the RR interval
Ventricular rate typically between 90-170 beats/min when untreated.
QRS complexes are typically narrow (although they can be wider if other
conditions are associated with it --such as bundle branch block)
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Final Thoughts
- ECG Solved
Week13
in the “Case of the Week” series
CAUTION:
Other conditions which have irregularly irregular R-R
intervals include:
Multifocal atrial tachycardia
Multifocal atrial premature beats
Atrial tachycardia or atrial flutter with varying AV block
Other abnormalities on this ECG:
(Just to be complete)
Q waves in leads III and aVF suggestive of but not
diagnostic of an inferior wall MI
Extensive “minor” T wave changes with low/flat T
waves noted in the inferior and lateral leads as well as
leads V4-6.
Leftward axis
This concludes this edition of the ECG puzzler. Contact me if you have questions!
For further reading:
Please see page 110 in Dale Dubin’s 6th edition
of Rapid Interpretation of EKG’s
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