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The Clinical Picture
Presumed premature ventricular contractions
Moises Auron, MD
Staff, Department of Hospital Medicine
and Center for Pediatric Hospital Medicine,
Cleveland Clinic
DonAlD unDerwooD, MD
Section of Clinical Cardiology, Department
of Cardiovascular Medicine, Cleveland Clinic
The CliniCal PiCTure
A 52-year-old man with atrial fibrillation due to severe chronic obstructive pulmo-
nary disease was admitted to the hospital with
an exacerbation of his lung disease. Telemet-
ric monitoring showed what appeared to be
premature ventricular contractions, and so an
electrocardiogram was obtained (figure 1).
What is the diagnosis? Is a cardiology con-
sult warranted?
■ AN ABERRANT CONDUCTION PATTERN
The finding seen in this electrocardiogram is
known as the Ashman phenomenon, an ab-
errant conduction pattern seen in atrial dys-
rhythmias, mainly atrial fibrillation, atrial
tachycardia, and atrial ectopy, when a relative-
ly long cycle is followed by a relatively short
cycle. The beat terminating the short cycle of-
ten has the morphology of right bundle branch
block.
This pattern was first described by Gouaux doi:10.3949/ccjm.78a.10155
figure 1. The electrocardiogram shows atrial fibrillation. The sixth beat has a long cycle (A), with a short
subsequent cycle (B). It is followed by two aberrantly conducted beats (white and black arrows). In lead V1,
morphology similar to right bundle branch block is evident (rsR’) in the first aberrant beat (white arrow),
with a QRS duration of 120 msec. The second aberrant beat has an rSR’ morphology.
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CLEVELAND CLINIC JOURNAL OF MEDICINE VOLUME 78 • NUMBER 12 DECEMBER 2011 813
auron and underwood
and Ashman in 1947; however, the aberrant
conduction of supraventricular impulses was
first described by Lewis in 1910.1,2
Ashman phenomenon
and right bundle branch block
The three criteria for the diagnosis of right
bundle branch block in adults are:
• A QRS duration of 120 msec or more
• An rsr', rsR', or rSR' in leads V1 or V2 (the
R' or r' deflection is usually wider than the
initial R wave)
• The duration of the S wave in I and V6 is
usually greater than that of the R wave or
is greater than 40 msec.3
Variation in the heart rate (due to atrial
fibrillation in this patient) affects the width
of the QRS interval; the refractory period of
a cycle is influenced by the RR interval of the
previous cycle. Therefore, if after a long cycle
with a consequent long refractory period, a
shorter cycle follows, then the beat terminat-
ing the short cycle is likely to be aberrantly
conducted because one of the bundle branch-
es is still in the refractory period. Because the
refractory period for the right bundle branch
is longer than that of the left bundle branch,
the right bundle branch block pattern is more
common.4
In our patient’s tracing (figure 1), the ab-
errantly conducted beat has the shortest cou-
pling intervals of any of the conducted beats
on the tracing. Although the RR interval pre-
ceding the short cycle is not the longest on
this tracing, it is moderately long, and so the
refractory period of the right bundle branch is
moderately long.
The Ashman pattern vs ventricular
premature beat
Atrial arrhythmias cause a variation in the
refractory period of the bundle branches and
the ventricular conduction system, and this
explains why the Ashman phenomenon oc-
curs more often in this setting. It is impor-
tant to distinguish the aberrant conduction
seen in the Ashman phenomenon, which
electrophysiologically is restricted to the His-
Purkinje system, from premature ventricular
complexes and ventricular tachycardia.
The current criteria used to distinguish
the Ashman phenomenon were described by
Fisch5,6:
• A relatively long cycle immediately pre-
ceding the cycle terminated by the aber-
rant QRS complex: a short-long-short
interval is even more likely to initiate
aberration. The aberration can be left or
right bundle branch block, or both, even
in the same patient.
• Right bundle branch block morphology,
with normal orientation of the initial
QRS vector. Concealed perpetuation of
the aberration is possible, and so a series
of wide QRS supraventricular beats is
possible.
• Irregular coupling of aberrant QRS com-
plexes.
• Lack of a fully compensatory pause.
In figure 1, the second aberrantly con-
ducted beat is not as aberrant as the first,
even though it is even more premature than
the first. This can be explained because the
refractory period of the right bundle branch
has now shortened.
Also, the mechanism of aberrancy of the
second beat may be partly the result of con-
cealed perpetuation, ie, incomplete penetra-
tion of the His bundle depolarizations in ei-
ther direction with secondary abnormalities
of antegrade or retrograde conduction. This
pattern is not directly reflected on the sur-
face electrocardiogram but can be detected
on intracardiac electrophysiologic studies.7
In concealed perpetuation, instead of induc-
ing tachycardia, the extra stimuli are followed
by pauses that exceed the tachycardia cycle
length.8
Treated by managing the atrial arrhythmia
There is no specific treatment for the aber-
rant cycles. Rather, treatment is directed at the
atrial arrhythmia.9 Adequate control of the un-
derlying process and the atrial tachyarrhythmia
itself is important. In our patient, control of the
exacerbation of chronic obstructive pulmonary
disease and of the heart rate improved the ven-
tricular response to atrial fibrillation. ■
it is important
to distinguish
aberrant
conduction
from premature
ventricular
contractions
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814 CLEVELAND CLINIC JOURNAL OF MEDICINE VOLUME 78 • NUMBER 12 DECEMBER 2011
■ REFERENCES
1. fisch C, Knoebel SB. Vagaries of acceleration dependent
aberration. Br Heart J 1992; 67:16–24.
2. gouaux JL, Ashman r. Auricular fibrillation with aberra-
tion simulating ventricular paroxysmal tachycardia. Am
Heart J 1947; 34:366–373.
3. Surawicz B, Childers r, Deal BJ, et al; American Heart
Association electrocardiography and Arrhythmias Com-
mittee, Council on Clinical Cardiology; American College
of Cardiology foundation; Heart rhythm Society. AHA/
ACCF/HRS recommendations for the standardization and
interpretation of the electrocardiogram: part III: intraven-
tricular conduction disturbances: a scientific statement
from the American Heart Association Electrocardiography
and Arrhythmias Committee, Council on Clinical Cardiol-
ogy; the American College of Cardiology Foundation; and
the Heart Rhythm Society. Endorsed by the International
Society for Computerized Electrocardiology. J Am Coll
Cardiol 2009; 53:976–981.
4. Antunes e, Brugada J, Steurer g, Andries e, Brugada P.
The differential diagnosis of a regular tachycardia with a
wide QRS complex on the 12-lead ECG: ventricular tachy-
cardia, supraventricular tachycardia with aberrant intra-
ventricular conduction, and supraventricular tachycardia
with anterograde conduction over an accessory pathway.
Pacing Clin Electrophysiol 1994; 17:1515–1524.
5. fisch C, Knoebel SB, eds. Clinical Electrocardiography of
Arrhythmias. Armonk, NY: Futura Publishing Company,
2000:407.
6. gulamhusein S, Yee r, Ko PT, Klein gJ. Electrocar-
diographic criteria for differentiating aberrancy and
ventricular extrasystole in chronic atrial fibrillation: vali-
dation by intracardiac recordings. J Electrocardiol 1985;
18:41–50.
7. Josephson Me. Miscellaneous phenomena related to
atrioventricular conduction. In: Clinical Cardiac Electro-
physiology: Techniques and Interpretations. 3rd ed. Phila-
delphia, PA: Lippincott Williams & Wilkins, 2002:140-154.
8. Josephson Me. Recurrent ventricular tachycardia. In:
Clinical Cardiac Electrophysiology: Techniques and Inter-
pretations. 3rd ed. Philadelphia, PA: Lippincott Williams &
Wilkins, 2002:425–610.
9. Hope rr, Lazzara r, Scherlag BJ. The induction of
ventricular arrhythmias in acute myocardial ischemia by
atrial pacing with long-short cycle sequences. Chest 1977;
71:651–658.
ADDRESS: Moises Auron, MD, Department of Hospital
Medicine, M2 Annex, Cleveland Clinic, 9500 Euclid Avenue,
Cleveland, OH 44195; e-mail auronm@ccf.org.
ashman Phenomenon
Cme answers
Answers to the credit tests on page 846 of this issue
Essential tremor: 1D 2C
Bioidentical hormone therapy: 1D 2C
Heart failure in the frail: 1B 2B
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