Yamaguchi Syndrome: An Important Consideration in the Differential Diagnosis of Chest Pain in the Emergency Department

Non-obstructive hypertrophic cardiomyopathy, or apical hypertrophic cardiomyopathy (ApHCM), also referred to as Yamaguchi syndrome, is a type of hypertrophic cardiomyopathy (HCM) characterized by significant thickening of the left ventricular apex without blockage in the left ventricular outflow tract. It is a very rare variant of HCM. Patients with non-obstructive HCM often experience symptoms such as chest pain, palpitations, shortness of breath, and syncope, which may resemble those seen in various cardiovascular and non-cardiac conditions. Yamaguchi syndrome presents as a challenging yet manageable condition in the ED. Early recognition, accurate diagnosis, and appropriate management are crucial for better outcomes. We report a case of a young female who presented to the ED with breathlessness and chest pain. The ECG findings suggested acute coronary syndrome (ACS), but echocardiography and cardiac biomarkers indicated otherwise, leading to the diagnosis of Yamaguchi Syndrome.