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• Brugada Phenocopy or unmasked Brugada Syndrome: Does observation without therapy is sufficient?
  Sunil Roy T. Narayanan, Warkaa Al Shamkhani
  Published on: 12 July 2018

• Published on: 12 July 2018

  Brugada Phenocopy or unmasked Brugada Syndrome: Does observation without therapy is sufficient?

  • Sunil Roy T. Narayanan, Consultant Interventional Cardiologist Belhoul Speciality Hospital, Dubai, UAE
  • Other Contributors:
    • Warkaa Al Shamkhani, Cardiology Registrar

  Dear Editor,
  Cardiac death in patients with Brugada ECG changes and negative family history is still a debatable subject. Brugada Phenocopy (BrP) is an emerging phenomenon describing conditions inducing a Brugada-like electrocardiogram (ECG) manifestations in patients without true BS. Brugada Phenocopy is defined as ECG patterns suggestive of Brugada syndrome but developed secondary to various acquired etiologies other than congenital or genetic causes. BrP cases were reported secondary to electrolyte disturbances, myocardial infarction, acidosis, pulmonary embolism, electrocution injury etc. The pattern presents in relationship with an identifiable condition and normalizes upon resolution of the same. The number of BrP cases are steadily increasing and the number of conditions known to cause Brugada Phenocopy are also growing. The diagnostic criteria for Brugada Phenocopy are (1)
  I. An ECG Pattern that has a type -1 or type-2 Brugada morphology
  II. The patient has an indentifiable underlying condition.
  III. The ECG pattern resolves upon resolution of the underlying condition
  IV. The clinical pretest probability of true Brugada syndrome is low as determined by a lack of symptoms, medical history, and family history
  V. The results of provocative testing with a sodium channel blocker such as ajmaline, flecainide, or procainamide are negative
  VI. Provocative testing is not mandatory if surgical RVOT manipulation has...

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  Dear Editor,
  Cardiac death in patients with Brugada ECG changes and negative family history is still a debatable subject. Brugada Phenocopy (BrP) is an emerging phenomenon describing conditions inducing a Brugada-like electrocardiogram (ECG) manifestations in patients without true BS. Brugada Phenocopy is defined as ECG patterns suggestive of Brugada syndrome but developed secondary to various acquired etiologies other than congenital or genetic causes. BrP cases were reported secondary to electrolyte disturbances, myocardial infarction, acidosis, pulmonary embolism, electrocution injury etc. The pattern presents in relationship with an identifiable condition and normalizes upon resolution of the same. The number of BrP cases are steadily increasing and the number of conditions known to cause Brugada Phenocopy are also growing. The diagnostic criteria for Brugada Phenocopy are (1)
  I. An ECG Pattern that has a type -1 or type-2 Brugada morphology
  II. The patient has an indentifiable underlying condition.
  III. The ECG pattern resolves upon resolution of the underlying condition
  IV. The clinical pretest probability of true Brugada syndrome is low as determined by a lack of symptoms, medical history, and family history
  V. The results of provocative testing with a sodium channel blocker such as ajmaline, flecainide, or procainamide are negative
  VI. Provocative testing is not mandatory if surgical RVOT manipulation has occurred within the last 96 hours
  VII. Negative genetic testing (desirable but not mandatory because the SCN5A mutation is identifiable in only 20% to 30% of probands affected by true BrS63).
  Out of these I -V are mandatory for making a diagnosis of Brugada Phenocopy. Provocative test is necessary as the same clinical conditions producing Brugada phenocopy can also unmask true Brugada syndrome.
  The article "DKA-induced Brugada Phenocopy mimicking STEMI" by Abrahim C and Maharaj S (Heart Asia 2018; 10: e011027), describe a 47-year old lady with type 1 diabetes mellitus presenting with type -1 Brugada ECG pattern mimicking STEMI during diabetic ketoacidosis and electrolyte abnormalities which normalized after correction of the metabolic abnormalities. The authors have advised observation without any therapy. She had no positive studies for inducible VT, but authors have not commended on whether they have done a provocative test with sodium channel blockers to unmask true Brugada syndrome. not clear whether they have investigated this with a provocative challenge test for Brugada syndrome.

  The Brugada ECG pattern may be a transient phenomenon in individuals who do not have a genetically determined disease but should not always be considered benign. There is some evidence proposing that this transient ECG pattern is a risk factor for the development of life-threatening cardiac arrhythmias and should be aggressively treated. Recent researches have described the risk of cardiac events in patients with a Brugada ECG pattern, during acute medical situations. Juntilla et al. [2] collected data on 47 patients: 26 patients with the Brugada ECG pattern due to drugs or medications; 16 patients with this ECG pattern developed VF during a febrile episode and five related to electrolyte imbalances. Of the 47 subjects with an acute Brugada ECG pattern, 24 (51%) had malignant arrhythmias, with 18 patients developed sudden cardiac arrest.

  Type 2 or 3 Brugada ECG pattern can be observed among healthy subjects without risk for arrhythmias but type I, as seen in this patient, is not always benign. Since only 1-2% of cases of out of hospital arrest survive, primary prevention of sudden death or close follow up should be more emphasized in those cases.
  References:
  1. Baranchuk A, Nguyen T, Ryu MH, Femenía F, Zareba W, Wilde AA, et al. Brugada phenocopy: new terminology and proposed classification. Annals of Noninvasive Electrocardiology. 2012;17(4):299-314.
  2. Juntilla MJ, Gonzalez M, Lizotte E, Benito B, Vernooy K, Sarkozy A, et al. Induced Brugada-type electrocardiogram, a sign for imminent malignant arrhythmias. Circulation. 2008 Apr 8;117(14):1890-3.

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  Conflict of Interest:
  None declared.

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