[SCD-FORUM] 73S RE Brugada pattern post-PAF reversion. Dr. Perez Riera

[SCD Symposium]

Dear Silvano Diangelo from Argentina,
I'm Andres Ricardo Perez Riera from Brazil, and I'll answer your  
question.
A young adult (35 years old), male, with electrocardiographic pattern  
of IRBBB with superior axis and that presents a crisis of paroxysmal  
AF with no apparent cardiac or extracardiac cause (I am certain that  
you investigated hyperthyroidism and other causes for AF), falls in  
the category of idiopathic AF: essential, primary, lonely, or as  
Anglo-Saxon literature call it, "lone atrial fibrillation", which is  
defined as AF that appears with no evidence (clinical or lab) of  
structural heart disease or systemic disease. It represents 6% to 10%  
of the cases of AF, and in many cases it translates an increase of  
vagal tone, generally during the night (AF of vagotonic type),  
transitory and in rest. These apparently idiopathic cases may have a  
genetic basis, and stop being so. AF apparently without cause has  
been mapped in several chromosomes:
1) Dominant autosomal chromosome 10 in region 10q22-q23 (1);
2) One of the mapped genes, 10q22 in region DLG5, is a member of the  
family of the proteins called MAGUKs (Membrane Associated Gyanylate  
Kinase). This family mediates intracellular signs with function in  
the formation of cellular binds, in maintenance of cell form, and  
clustering of protein channels in cell surface (2);
3) A family with the mutation (S140G) in gene KCNQ1 (KvKQT1) of  
chromosome 11p15.5 was also identified. This KCNQ1 gene, encodes the  
pore that makes up the alpha subunit of I(Ks) channel. The analysis  
of this mutation revealed a gain in function in KCNQ1/KCNE1 and KCNQ1/ 
KCNE channels. This fact is in contrast with the negative effect or  
loss of function in KCNQ1 observed in long QT syndrome. Thus, the  
S140G mutation starts and maintains AF by reducing the duration of  
AP, and the refractory period of atrial cardiomyocytes (3).
First conclusion: in this patient it is necessary to perform a  
genetic study. Not only because of suspicion of Brugada syndrome, but  
to determine if AF is idiopathic or genetic.

This patient may have a cancelled from of Brugada that was unmasked  
by use of endovenous propafenone. Several papers show that Brugada  
syndrome may be unmasked with propafenone in this way (4).
Propafenone in Brugada syndrome may unmask VT crisis, both  
polymorphic and monomorphic (5).
It may cause J wave in inferior lead when injected in patients  
carriers of the so-called variant Brugada syndrome (6).
A case very similar to yours was presented last year (2005) by Aksay  
et al in Turkey, in which the patient presented acute AF, and when  
propafenone was administered to reverse AF, Brugada pattern appeared  
(7). A similar situation was observed by Beldner et al (8) in  
patients with AF treated with propafenone or with flecainide.
Second conclusion: your patient seems to have Brugada syndrome, and  
should be electrophysiologically studied. "It looks like a lion, and  
it is a lion." If positive, ICD.

References
1)       Brugada R, Tapscott T, Czernuszewic GZ, et al.  
Identification of a genetic locus for familial atrial fibrillation N  
Engl J Med 1997; 336:905-911);
2)       Shah G, Brugada R, Gonzalez O, et al. The cloning, genomic  
organization and tissue expression profile of the human DLG5 geneBMC  
Genomics 2002 3: 6.
3)       Chen YH, Xu SJ, Bendahhou S, et al. KCNQ1 gain-of-function  
mutation in familial atrial fibrillation. Science 2003; 299:251-254.
4)       Matana A, Goldner V, Stanic K, et al. Unmasking effect of  
propafenone on the concealed form of the Brugada phenomenon. PACE  
2000;23:416-418.
5)       Karaca M, Dinckal MH.Successful radiofrequency catheter  
ablation of idiopathic ventricular fibrillation presented as  
recurrent syncope and diagnosed by an implanted loop recorder. Acta  
Cardiol. 2006;61:481-484.
6)       Ozeke O, Aras D, Celenk MK, Exercise-induced ventricular  
tachycardia associated with J point ST-segment elevation in inferior  
leads in a patient without apparent heart disease: a variant form of  
Brugada syndrome? J Electrocardiol. 2006; 39:409-412.
7)       Aksay E, Okan T, Yanturali S.Brugada syndrome, manifested by  
propafenone induced ST segment elevation. Emerg Med J. 2005;22:748-750.
8)       Beldner S, Lin D, Marchlinski FE.Flecainide and propafenone  
induced ST-segment elevation in patients with atrial fibrillation:  
clue to specificity of Brugada-type electrocardiographic changes. Am  
J Cardiol. 2004;94:1184-5.
Cordially,
Andrés Ricardo Pérez Riera
Jefe del Sector de Electro-Vectocardiologia  de la disciplina de  
Cardiologia del  ABC. Facultad de Medicina del ABC (FMABC),  
Foundación del ABC (FUABC) - Santo André -  Sao Paulo - Brasil. Rua  
Sebastiao Afonso  885 - Zip Code: 044417-100- Jardim Miriam   S.P   
Brazil

--
Dr. Sergio Dubner
President of Scientific Committee

Dr. Edgardo Schapachnik
President of Steering Committee


>
> I would like to ask Dr. Andres Perez Riera about a 35-year-old,  
> male patient, with no structural heart disease or family history of  
> SCD, baseline ECG with incomplete right bundle branch block with  
> superior axis, who presents for the first time with Paroxysmal  
> Atrial Fibrillation, which after being reverted with oral  
> propafenone 600 mg (UD), induces ECG with Brugada pattern.
> What is the prognosis? Therapeutics?
> Does he need an additional screening (genetic, EPS)?
> Is he really a Brugada patient or is this just the effect of the  
> drug, producing Brugada-like pattern?
>
> Thank you very much.
>
> Kind regards,
> Dr. Silvano Diangelo
> Argentina
>
>

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