Understanding the EKG changes in methemoglobinemia

Methemoglobin is a form of hemoglobin that has been oxidized, changing its heme iron configuration from the ferrous to the ferric state. Unlike normal hemoglobin, methemoglobin does not bind oxygen and as a result, cannot deliver oxygen to the tissues. At the presentation in the emergency department, an electrocardiogram (EKG) is usually performed as a reflex for patients admitted for shortness of breath to rule out acute coronary syndrome. Very limited data is available on EKG abnormalities in patients with methemoglobinemia. In this study, we retrospectively analyzed the pattern of EKG changes in patients with methemoglobinemia.