Abnormal Repolarization, Spot Diagnosis?: Difference between revisions

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m (New page: {{NHJ| |mainauthor= '''A.A.M. Wilde, N.A. Blom''' |edition= 2007:03,114 }} Figure 1|thumb A boy with a birth weight of 3.030 g was born by caesarean ...)
 
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[[Puzzle_2007_03_114_Answer|Answer]]
[[Puzzle_2007_03_114_Answer|Answer]]
The 12-lead ECG shows sinus rhythm with a frequency
of 98 beats/min. The PQ interval is 140 msec and the
QRS width 60 msec (normal value for a neonate). The
vertical axis is normal for the age. Repolarisation is
grossly abnormal and clearly alternates in morphology
every other beat. This T-wave alternans is visible in
every lead but most clearly in lead V4. The QTc interval
is severely prolonged and varies between 665 and 689
msec. The P wave fuses with the terminal part of the
T wave and intermittently was not conducted (i.e.
functional 2:1 block, not shown).
The combination severe QT-interval prolongation
and syndactyly is classical for type 8 LQTS also referred
to as Timothy syndrome.1 It presents frequently at birth
with life-threatening polymorphic arrhythmias in the
setting of severe QTc prolongation. Besides syndactyly
(present in virtually all cases) extra cardiac features include
congenital defects (ASD, VSD), hypoglycaemia,
and autism. In 20% a hypertrophic cardiomyopathy is
shown, as was also seen in our case on echocardiography.
2 Left ventricular systolic function was decreased
(left ventricular shortening fraction 20%). DNA
analysis in our case also revealed the de novo CaV1.2
missense mutation G406R.<cite>Splawski</cite><cite>LoANjoe</cite>
''Postnatal course''
After one month, he developed recurrent torsades de
pointes and syncope. Mexiletine 15 mg/kg and oral
potassium supplementation were added to the therapy
and an extracardiac single-chamber implantable cardioverter-
defibrillator (ICD) was inserted at 4 months of
age. He received numerous ICD shocks and eventually
died at the age of two years after cervical sympathectomy.
==References==
<biblio>
#Splawski pmid=15454078
#LoANjoe pmid=16360093
</biblio>

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