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