Yamaguchi syndrome, or apical (Ap) hypertrophic cardiomyopathy (HCM), is a subtype of HCM that primarily affects the left ventricular apex. The diagnosis of ApHCM is often missed or delayed, as its presenting symptoms are very similar to acute coronary syndrome. Diagnosis can also be missed or delayed due to providers being unfamiliar with the condition—consequently, this condition is usually detected incidentally. However, once diagnosed properly, ApHCM has a good long-term outcome.
Some studies have suggested that ApHCM is particularly common in individuals of East Asian descent. The vast majority of patients with ApHCM are hypothesized to be asymptomatic, but the most common presenting symptom is chest pain, followed by palpitations, dyspnea, and syncope. It may also manifest itself as aberrant events such as atrial fibrillation, myocardial infarction, ventricular fibrillation, and/or heart failure.
The key ECG findings of ApHCM include:
The classic radiographic features of ApHCM include a "spade-like" configuration, or ace-of-spades sign, over the left ventricle.
The diagnosis of ApHCM can be made with echocardiography, left ventriculography, computed tomography, or most accurately, cardiac magnetic resonance imaging. Multimodality imaging with several of these imaging techniques provides the most accurate assessment.
Management for ApHCM is the same as it is for patients with HCM. Patients who are symptomatic are initially treated with medical therapy and should be monitored for ventricular tachyarrhythmias. However, ApHCM is typically associated with low risk and almost never requires implantable cardioverter defibrillator placement for primary prevention.