Scarce Duet in One Heartbeat: A Case Report on Yamaguchi and Myocardial Bridging

Among the various types of hypertrophic cardiomyopathies (HCM) is an apical hypertrophic cardiomyopathy (ApHCM) variant, also known as Yamaguchi syndrome. It is a rare condition mostly found in Japanese patients and is characterized by the special Ace-of-Spades morphology of the left ventricular cavity. The coexistence of ApHCM and myocardial bridging is an uncommon finding. This rare association may create a complex arrhythmogenic and ischemic substrate, potentially increasing the risk of adverse cardiac events. In our patient, echocardiography demonstrated an apical wall thickness of 17 mm, a left ventricular outflow tract (LVOT) maximum peak gradient of 3.45 mmHg, and a LVOT mean gradient of 2.47 mmHg, along with a global longitudinal strain (GLS) value of −15.8%, consistent with a non-obstructive LVOT physiology. While its symptoms coincide with those of acute coronary syndrome (ACS), clinicians should maintain a high index of suspicion for this disease, as it is often unrecognized. This paper documents the rare coexistence of Yamaguchi syndrome and myocardial bridging in a patient with a previous history of cardiac arrest, highlighting its rarity, discussing the diagnostic challenges due to symptoms mimicking acute coronary syndrome (ACS), and emphasizing the importance of careful management and follow-up in affected patients.