Brugada Phenocopy Switch: A Surprising Transition of the Electrocardiogram Pattern from Type 1 to Type 2 in a Case of Insecticide Poisoning with Methemoglobinemia: A Unique Case Report

A BSTRACT Brugada syndrome (BrS) is an autosomal dominant, heritable channelopathy with variable expression characterized by a coved-type ST-segment elevation (≥2 mm) followed by a negative T wave of ≥1 mm in the right precordial leads on an electrocardiogram (ECG). This syndrome can present spontaneously or be provoked by class I antiarrhythmic drugs with an increased risk of sudden cardiac death during rest, sleep, or febrile episodes. Brugada phenocopy/pattern (BrP) refers to similar ECG findings in the absence of true BrS induced often by certain medications or toxins. We report a case of suicidal insecticide poisoning containing biological extracts leading to methemoglobinemia and myocarditis in a patient, unmasking the Brugada pattern on the ECG. The patient initially presented with typical symptoms of vomiting, mild abdominal discomfort with severe breathlessness. ECG revealed a Brugada Type 1 pattern. During the course of treatment, this ECG pattern transitioned from Type 1 to Type 2 on day 5 of admissions, thus indicating dynamic changes in the cardiac electrical activity. BrP ECG is not an uncommon finding and can be unmasked in cases of poisoning with agents that block sodium channels in the myocardium. In addition, stress cardiomyopathy and toxic myocarditis can precipitate this ECG pattern. To choose the right management strategy, it is essential to properly differentiate BrS from its phenocopy by considering symptoms, provocative factors, and family history and to highlight the importance of regular follow-up and proper patient education.