A rare case of silent transmural myocardial infarction with diffuse ST elevations complicated by concomitant severe hyperkalemia

It is well described that certain group of patients do not display the typical symptoms of myocardial infarction (MI). Elderly patients, diabetics and those with previous coronary artery bypass graft surgery are at high risk for silent MI. The diagnosis of Acute MI in the emergency room (ER) is mainly based on the electrocardiogram (EKG) findings of ST elevations or new onset left bundle branch block which is supported by the clinical presentation and positive biomarkers when present. The diagnoses can sometimes become challenging when the patient is asymptomatic and has coincidental finding of hyperkalemia with diffuse ST segment elevations simulating that seen with electrolyte disturbance. Despite the well known pseudoinfarction pattern of hyperkalemia, acute MI should be ruled out first. A high index of suspicion is needed, especially in high risk patients. We think that in rare clinical situation when the diagnosis is in doubt, MI should be ruled out, as time has a high impact on patient mortality. An urgent bedside echocardiogram is very beneficial in excluding regional wall motion abnormalities and preventing any delay in destination therapy for transmural MI. We present a 67 years old female with history of diabetes and chronic kidney disease sent by her nephrologist to the ER for severe hyperkalemia (Potassium 7.2 milliequivalent/L). She was found to have ST elevations on EKG despite having no chest pain or distress. On cardiac catheterization she had a total occlusion of the proximal left circumflex artery, with a filling defect consistent with large thrombus.