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Wide Complexes Intervening Regular Sinus Rhythm - 2: Difference between revisions
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Wide Complexes Intervening Regular Sinus Rhythm - 2 (view source)
Revision as of 19:28, 8 October 2007
, 8 October 2007no edit summary
m (New page: {{NHJ| |mainauthor= '''A.A.M. Wilde''' |edition= 2007:01,033 }} Figure 1|thumb A 38-year-old male patient presents with palpitations. He is not sufferi...) |
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[[Puzzle_2007_1_33_Answer|Answer]] | [[Puzzle_2007_1_33_Answer|Answer]] | ||
The ECG shows sinus rhythm with a mean rate of 60 | |||
beats/min. There is some sinus arrhythmia present. | |||
Conduction intervals are normal (PR 150 ms, QRS | |||
90 ms). Repolarisation abnormalities are present in the | |||
right precordial leads V1 to V3 (terminal negative T | |||
waves) and the ST-T segment in lead V4 is flat. | |||
Two wide complexes are seen, the third and tenth | |||
QRS complex. Both share a similar morphology with | |||
a left bundle branch block and an almost vertical axis. | |||
There is no discernible P wave prior to these wide QRS | |||
complexes and the first is followed by a complete compensatory | |||
pause in contrast to the second which does | |||
not influence the underlying sinus rhythm. The | |||
morphology of the wide complexes, the lack of P waves | |||
and the presence of a complete compensatory pause all | |||
point to a ventricular origin of this activity. Based on | |||
the morphology, an origin in the right ventricular | |||
outflow track (RVOT) is likely. In combination with | |||
the ST-T segment abnormalities one should consider | |||
arrhythmogenic right ventricular dysplasia (ARVD/C) | |||
and additional imaging should be performed. | |||
There are several electrocardiographic peculiarities | |||
in this electrocardiogram. First, the second ventricular | |||
extrasystole is not intervening with the sinus rhythm. | |||
This is referred to as an interpolated ventricular extrasystole. | |||
This is a relatively rare phenomenon usually | |||
seen with a slow heart rate. In this case the heart rate | |||
is not really slow. | |||
Second, the conducting P wave of the P wave | |||
following this extrasystole has a longer PR interval | |||
(figure 2). This phenomenon is referred to as concealed | |||
retrograde conduction; i.e. the ventricular extrasystole | |||
conducts retrogradely in the AV node slowing the | |||
anterograde conducting P wave. In the case of the first | |||
extrasystole retrograde conduction actually blocks the | |||
antegrade P wave completely. | |||
In conclusion, this is a sinus rhythm with ventricular | |||
extrasystoles originating in the RVOT (one of them | |||
interpolated) with retrograde penetrance in the AV | |||
node. The ST-T segment abnormalities in combination | |||
with the extrasystole’s origin suggest the presence of | |||
ARVC. | |||