Revised: December 24, 2013
Accepted: January 15, 2014
Published online: March 26, 2014
Processing time: 128 Days and 10.6 Hours
Brugada phenocopies (BrP) are clinical entities that are etiologically distinct from true congenital Brugada syndrome. BrP are characterized by type 1 or type 2 Brugada electrocardiogram (ECG) patterns in precordial leads V1-V3. However, BrP are elicited by various underlying clinical conditions such as myocardial ischemia, pulmonary embolism, electrolyte abnormalities, or poor ECG filters. Upon resolution of the inciting underlying pathological condition, the BrP ECG subsequently normalizes. To date, reports have documented BrP in the context of singular clinical events. More recently, recurrent BrP has been demonstrated in the context of recurrent hypokalemia. This demonstrates clinical reproducibility, thereby advancing the concept of this new ECG phenomenon. The key to further understanding the pathophysiological mechanisms behind BrP requires experimental model validation in which these phenomena are reproduced under strictly controlled environmental conditions. The development of these validation models will help us determine whether BrP are transient alterations of sodium channels that are not reproducible with a sodium channel provocative test or alternatively, a malfunction of other ion channels. In this editorial, we discuss the conceptual emergence of BrP as a new ECG phenomenon, review the progress made to date and identify opportunities for further investigation. In addition, we also encourage investigators that are currently reporting on these cases to use the term BrP in order to facilitate literature searches and to help establish this emerging concept.
Core tip: Diagnostic distinctions between Brugada phenocopies (BrP) and Brugada syndrome (BrS) are: (1) BrP patients have a reversible underlying condition and upon resolution of this condition, the electrocardiogram normalizes; (2) BrP patients have a low pretest probability of BrS as opposed to a high pretest probability in patients with true congenital BrS; and (3) BrP patients have a negative sodium channel blocker test, while patients with BrS have a positive test. The different electrocardiographic response to the provocative challenge highlights a pathophysiological divergence when comparing BrP and BrS. This suggests alternative underlying mechanisms with various genetic, structural and environmental interactions yet to be elucidated.