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Cardiac Corner: Name that Arrhythmia
By Jon Atkinson, BS, RPSGT
T
his is the fifth in a series of recurring columns that will keep
cardiac arrhythmias fresh in the minds of sleep technologists.
The goal is to present arrhythmias from actual recordings and to
analyze them using the principles presented in the recent articles
on cardiac arrhythmias in A2Zzz.1
Examine Figure 1. This is a 30-second window. Proceed as
follows:
Step 1. Look at the P wave. P waves are present and have the
same appearance.
Step 2. Look at the QRS complex. QRS complexes are present;
all QRS complexes look the same.
Step 3. Examine the relationship between P wave and QRS
complexes. There is a 1:1 relationship between the P waves and
the QRS complexes.
Step 4. Examine the intervals (P-R interval and QRS interval). The P-R wave interval is within normal limits. The QRS
interval is narrow and within normal limits (0.04 - 0.11 seconds).
Step 5. Examine the rhythm. The rhythm is fairly regular
throughout the 30-second epoch.
Step 6. Determine the rate. The rate is about 38 beats per
minute.
Examine Figure 2. This is a 10-second window. Proceed as
follows:
Step 1. Look at the P wave. No P waves are present during
the event. A P wave is present following the event and appears to
have the same configuration as the other P wave that is present.
Step 2. Look at the QRS complex. QRS complexes are present
except during the event.
Step 3. Examine the relationship between P wave and QRS
complexes. There is a P wave for each QRS complex and a QRS
complex for every P wave; therefore, the P:QRS ratio is 1:1.
Step 4. Examine the intervals (P-R interval and QRS interval). The P-R interval is normal at 0.12-0.20 seconds. The QRS
interval is narrow outside the event limits and increased (< 0.12
seconds) during the event.
Step 5. Examine the rhythm. The atrial rhythm is irregular due
to the pause. The ventricular rhythm is irregular due to the pause.
Jon Atkinson, BS, RPSGT
Step 6. Determine the rate. The atrial and ventricular rate is
about 45 beats per minute before and after the event. The distance
between the R waves in the event is about 6 seconds with a resultant heart rate of 10 bpm.
Discussion
Figure 1 is an example of sinus bradycardia. All of the parameters are intact except that the heart rate is too slow. In the classic
definition of bradycardia, the heart rate is < 60 beats per minute.
According to the AASM scoring manual, sinus bradycardia should
be scored for a sustained heart rate of < 40 beats per minute.2
Figure 2 is an example of asystole. The AASM scoring manual
states, “Score asystole for cardiac pauses greater than 3 seconds,
ages 6 to adult.” The duration of the event in Figure 2 is 6.1
seconds. It is the longest of five or six events lasting longer than 3
seconds, all occurring in rapid eye movement (REM) sleep without associated apneic events or arousals. See Figure 3.
Technical Considerations
To adequately assess the QRS interval duration, window widths
of 10 seconds, or if needed as low as five seconds, are recommended. In Figure 3, the escape beat (i.e., the beat following the pause)
is better seen at a 10-second window than the 30-second window.
The beat after the 6-second pause is atrial (P wave is seen); the
beats following the 3 and 4-second asystoles are junctional with
an absence or inversion of the P wave. Additionally, recording
several ECG lead combinations simultaneously, or changing to a
lead combination that shows the best P wave, will be helpful for Pwave identification and P-R interval assessment. Also note in Figure 3 that the “PulseR” channel derived from the pulse oximeter is
inaccurate, but the “RR” channel measuring the distance between
R waves with a cardiotachometer is accurate and shows the beat to
beat variation in heart rate.
Intervention
Your institution should have in place a clear, well-defined policy
describing responses to “emergency” situations and occurrences
including cardiac arrhythmias. The arrhythmias described in this
article require documentation if occurrences are isolated; patient
assessment including blood pressure, level of consciousness, and
chest pain; and notification of the medical director or designee if
occurrences are recurring or sustained. Of course, the Emergency
Medical System should be activated if the arrhythmia is unabated,
chest pain or alteration of consciousness occurs, low or high blood
pressure occurs, or on order of the Medical Director or designee.
References
Jon Atkinson, BS, RPSGT, is the AAST
President. He has been in the sleep field
for 27 years, and he currently works as a
self-employed consultant in sleep medicine technology.
1. Atkinson J. Scoring center: scoring cardiac dysrhythmias part 2. A2Zzz 2008;17(1):30-32.
2. American Academy of Sleep Medicine. The AASM
manual for the scoring of sleep and associated events: rules,
terminology and technical specifications. Westchester, Ill:
American Academy of Sleep Medicine; 2007. 
A2Zzz 18.2 | June 2009
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Figure 1. 30-second window.
 Continued on Page 24
Figure 2. 10-second window.
A2Zzz 18.2 | June 2009
 Continued from Page 23
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Figure 3. Multiple asystolic events with durations of 6, 3 and 4 seconds in a single, 30-second epoch.
The AAST acknowledges and thanks the following organizations for their generous
support and for investing in the future of the sleep technology profession as AAST
Supporter Members:
American
American Associatio
Associatio nn
of
of Sleep
Sleep TTechnologists
echnologists
AAST
ResMed
Respironics, Inc.
AAST
Cadwell
Laboratories, Inc.
2009
2009
American Associatio
Associatio nn
American
of Sleep
Sleep TT echnologists
echnologists
of
American Associatio
Associatio nn
American
of Sleep
Sleep TT echnologists
echnologists
of
AAST
Cardinal Health &
MVAP Medical
Supplies, Inc.
2009
A2Zzz 18.2 | June 2009
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