[SCD-FORUM] 49E RE: Asymptomatic patient with Brugada syndrome. Dr. Furlani

[SCD Symposium]

Dear Dr Li:
   You've got a point there, but another possibility is that TWA test  
is not as good to detect repolarization problems in the RV as it is  
in the LV (being BrS a predominantely RV channelopathy).Moreover,  
maybe the timing of the TWA test was not the most appropriate in both  
German and Japanese studies cited by Dr Brugada. Why does a patinent  
with a Type I ECG remains asymptomatic for 5 to 10 years and then die  
suddenly or have 3 episodes of syncope the same day? TWA test would  
be abnormal in this patient before experiencing SCD or recurrent  
syncope?
   We are just warming up, there is a long way to go.
   My best regards,

   Aldo Alberto Furlani MD
   Cardiac Electrophysiologist
   Consultant Cardiologist
   Heart Institute of the Caribbean
   Mandeville
   Jamaica
   afurlani at caribbeanheart.com
   www.caribbenheart.com

--
Dr. Sergio Dubner
President of Scientific Committee

Dr. Edgardo Schapachnik
President of Steering Committee


>
> Dr. Li,
> Has genetic research analysis ruled out genetic allele chimerism  
> (at the
> time of organogenesis and embryological differentiation) to explain  
> the
> phenotypic variety of channelopathies or numerous clinical  
> manifestations? Another
> words are some alleles more likely to find or gravitate towards the  
> eighth
> nerve, RV, vs LV etc., while other regions of pacemaker cells  
> remain entirely
> normal?
> Richar-Ray/dba Richard Ray Jordan, M.D., SFM
>
> --
> Dr. Sergio Dubner
> President of Scientific Committee
>
> Dr. Edgardo Schapachnik
> President of Steering Committee
>
>>
>> Then we should ask oursselves why is so Dr. Ramon Brugada. Without  
>> a clear understanding of the disease nature, we may be always in  
>> the dark in terms of risk stratification. If Brugada syndrome were  
>> a primary repolarization disorder, one would expect the  
>> repolarization instability such as microvolt T wave alternans  
>> prior to the onset of VT/VF. As a matter of fact, the majority of  
>> VT/VF patients showed positive late potentials ( Arch Cardiol Mex.  
>> 2006 Jan-Mar;76(1):52-8 ). Recently Dr. Shimizu's group  
>> demonstrated both depolarization and repolarization abnormalities  
>> [ Pacing Clin Electrophysiol. 2006 Oct;29(10):1112-21]. In the  
>> past our main focus was the consequence of reduced INa to the  
>> phase 1 repolarization in the RV epicardium and the transmural  
>> dispersion of repolarization, which may be part of the story. The  
>> slow activation propagation in ROVT region due to reduced sodium  
>> current itself should not be overlooked Am J Physiol Heart Circ  
>> Physiol. 2006 Jul 28; [Epub ahead of print]
>> .
>> Channelopathies especially SCN5A mutations can lead to structural  
>> abnormalities although many are undetectable by routine work up.  
>> Those structural alterations (macroscopic or microscopic) could  
>> also be the substrate to re-entrant ventricular tachyarrhythmias  
>> and sudden VT/VF death.
>>
>> Sincerely,
>>
>> Li Zhang, MD
>> LDS Hospital,
>> University of Utah School of Medicine
>> Salt Lake City, UT
>> USA
>>
>>>
>>> No that i know of. There are two studies which looked at TWA  
>>> (Japan and
>>> Germany) in Brugada syndrome. Neither one showed any correlation  
>>> with risk.
>>>
>>> Dr. Ramon Brugada MD FACC
>>> Associate Professor of Medicine
>>> Canadian Research Chair Genetics of Arrhythmias
>>> University of Montreal
>>> Director Clinical Cardiovascular Genetics Center
>>> Montreal Heart Institute
>>> 5000 Rue Belanger
>>> Montreal, QC H1T 1C8
>>> Canada
>>> ramon at brugada.org
>>>
>>>
>>>
>>>>
>>>> Dear Dr. Ramon Brugada,
>>>> As you have discussed in the answer to the question for an  
>>>> asymptomatic
>>>> patient with brugada syndrome, the use of EPS to risk stratify
>>>> asymptomatic patient is very controversial. The first symptom  
>>>> may be
>>>> sudden death in such patients. In such a scenario is there any  
>>>> role for
>>>> microvolt T wave alternans for risk stratifications and to  
>>>> decide the need
>>>> for ICD?
>>>>
>>>> Dr. Sunil Roy.  MD, DM
>>>> Senior Lecturer in Cardiology
>>>> Medical college, Calicut, Kerala, India
>>>> Email: sunilroytn at calicutmedicalcollege.ac.in
>>>>
>>>>
>>>>

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