A 46-Year-Old Man Presenting With Chest Pain Due to Apical Hypertrophic Cardiomyopathy (Yamaguchi Syndrome) Diagnosed by Multimodal Cardiac Imaging

Background:Apical hypertrophic cardiomyopathy (ApHCM), also known as Yamaguchi syndrome, is a rare variant of hypertrophic cardiomyopathy characterized by the thickening of the left ventricle apex (>15 mm) and giant negative T-waves on the precordial leads of the electrocardiogram (ECG), which can present symptoms and electrocardiographic changes that mimic acute coronary syndrome (ACS).This report describes the case of a 46-year-old man with chest pain and giant T-wave inversion on ECG, requiring multimodal cardiac imaging to diagnose ApHCM (Yamaguchi syndrome) and exclude the diagnosis of coronary artery occlusion and myocardial infarction. Case Report:We report the case of a 46-year-old man who presented to the Emergency Department with typical chest pain.His ECG revealed significant alterations highly suggestive of ACS, including ST-segment depression and giant negative T-waves (>10 mm) in leads V4-V6.Despite this presentation, serial high-sensitivity troponin levels remained consistently within the normal range.Coronary computed tomography angiography (CCTA) revealed non-obstructive coronary arteries but indicated increased apical left ventricular (LV) wall thickness with characteristic trabeculation, raising suspicion for ApHCM.Transthoracic echocardiography (TTE) confirmed pronounced apical LV thickening (20 mm) and a reduced Global Longitudinal Strain (GLS) of -14.3%.Cardiac magnetic resonance (CMR) imaging provided a definitive diagnosis, identifying significant apical hypertrophy with systolic obliteration of the LV cavity and quantifying multifocal myocardial fibrosis at 6% of the LV mass.The patient's symptoms improved significantly with medical therapy, including losartan, metoprolol, and trimetazidine. Conclusions:This case highlights the critical diagnostic challenge of ApHCM masquerading as ACS.It underscores the indispensable role of a multimodal imaging approach-integrating ECG, TTE, CCTA, and CMR-for an accurate diagnosis, particularly for identifying underlying myocardial fibrosis and guiding appropriate patient management.