Brugada phenocopies are the leading differential diagnosis of Brugada syndrome

Abstract

Please submit letters for the editor's consideration within three weeks of receipt of Clinical Medicine. Letters should ideally be limited to 350 words, and sent by email to: clinicalmedicine@rcplondon.ac.uk Brugada phenocopies are the leading differential diagnosis of Brugada syndromeEditor -We read the literature review on Brugada syndrome (BrS) by Sheikh and Ranjan with great interest (Clin Med 2014;5:482-9). Their manuscript provides a concise review of BrS and identifi es associated differential diagnoses. We would like to direct the authors to our work on Brugada phenocopies (BrP). 1 BrP are the leading differential diagnosis of true congenital BrS. Many of the underlying BrS differential diagnoses that the authors mention are actually various underlying etiologies of BrP. We would like to provide the authors with a brief explanation of BrP and its clinical distinction from BrS.BrP are clinical entities that present with identical ECG patterns to those of true congenital BrS but are elicited by various other clinical circumstances. 1 Conditions that induce BrP are characterised into six etiological categories: metabolic conditions, mechanical compression, myocardial ischemia and pulmonary embolism, myocardial and pericardial disease, ECG modulations and miscellaneous. 1 Our international registry and online educational portal provides an updated registry of BrP cases along with the diagnostic criteria. 2 Many of the conditions that the authors mention as part of their differential diagnosis for a Brugada ECG pattern are confi rmed causes of BrP, including acute pericarditis, myocardial ischemia, pulmonary embolism, hyperkalemia, hypercalcemia, hypothermia and pectus excavatum. BrP form a group of heterogeneous conditions that are perhaps the most diffi cult to differentiate from true congenital BrS due to identical ECG patterns. Distinguishing between BrP and BrS relies on a series of clinical and ECG characteristics (

Brugada syndrome

“…One of the leading differential diagnoses of BrS are Brugada phenocopies (BrP), which are ECG patterns that are identical to true congenital BrS. BrP is elicited by various circumstances including acute pericarditis, myocardial ischaemia, pulmonary embolism, pectus excavatum, hyperkalemia, hypercalcemia, hypothermia and compressive mediastinal tumours [76][77][78][79][80][81]. The pathophysiology behind BrP may be similar to the underlying pathophysiology of BrS including structural, depolarisation, and/or repolarization abnormalities.…”

Athletes with channelopathy may be eligible to play

“…However, BrS is a clear-cut electrophysiological diagnosis [ 37 ]. A diagnostic type 1 ECG is defined as a spontaneous high take-off and downsloping ST-segment elevation of more than 2 mm above the baseline J‑point in the right precordial leads (V1–3) followed by a negative T‑wave [ 1 , 2 , 37 , 38 ]. If there is suspicion of BrS high lead placement of V1-3 in the second and third intercostal spaces may unmask a Brugada pattern.…”

“…Besides, the mechanism of inducing a fatal arrhythmia in BrS with a drug challenge test is different from exercise-induced VT/VF. Furthermore, the Brugada pattern should be distinguished from Brugada phenocopies and early repolarisation [ 27 , 37 , 38 , 41 ]. The latter is a normal finding in highly trained endurance athletes [ 27 , 38 , 41 ].…”

“…The latter is a normal finding in highly trained endurance athletes [ 27 , 38 , 41 ]. Brugada phenocopies are a group of heterogenous conditions with Brugada-like ECG findings, lack of symptoms suggestive of BrS, negative family history of BrS or SCA/SCD, negative drug challenge test, and negative genetic testing [ 37 ]. In addition, SCA/SCD in BrS is generally unrelated to exercise, but occurs most often during sleep.…”

“…In a large Italian screening study, young athletes with LQTS—0.6% of all non-eligible athletes—were disqualified on a presumed risk of an exercise pro-arrhythmic trigger of VT/VF [ 37 ]. During follow-up no cardiac events in the disqualified athletes were reported [ 47 ].…”