To the Editor—Is it really COVID-19?

We read with great interest the article by Chang and colleagues,¹ in which they reported COVID-19 infection unmasking Brugada syndrome but they report, finally, that it is the fever that is unmasking the Brugada pattern. We want to congratulate the authors on their article, which demonstrates that COVID-19 infection may be another etiology to expose a Brugada pattern.

We agree with most of the statements provided in the present work, but our main concern is the lack of rigor, since it is nothing new that fever is capable of unmasking Brugada pattern and this hallmark has already been previously reported in large cohort series. Dumaine and colleagues² were the first to link temperature with the function of a mutant SCN5A sodium channel. In 2002, Porres and colleagues³ reported that an increase in temperature may be the most important factor in revealing the electrical anomalies and activating ventricular arrhythmias. Two studies demonstrated that in unselected populations with fever, type 1 Brugada electrocardiography may be seen. Mizusawa and colleagues⁴ demonstrated that patients who had fever-induced type 1 electrocardiography have an increased risk for syncope and ventricular fibrillation. Michowitz and colleagues⁵ reported that premature inactivation of the sodium channel is accentuated at higher temperatures, suggesting that febrile states may unmask certain Brugada syndrome patients or temporarily increase the risk of arrhythmia, mainly in Caucasian male patients. So, we would like it to be learned that any condition that predisposes to fever may unmask a Brugada pattern—not just the COVID-19 infection.