Yamaguchi Syndrome
Yamaguchi Syndrome – Overview
Definition:
Yamaguchi syndrome is a rare variant of apical hypertrophic cardiomyopathy (ApHCM), first described by Dr. Yamaguchi in Japan in 1979. It is characterized by predominant hypertrophy of the left ventricular (LV) apex, often without outflow tract obstruction.
Epidemiology
- More common in East Asian populations, especially Japan.
- Represents 15–25% of HCM cases in Japan, but <10% in Western countries.
- Can be familial (autosomal dominant) or sporadic.
Pathophysiology
- Hypertrophy confined to apical region of the LV.
- Preserved or increased ejection fraction.
- Abnormal myocardial architecture → diastolic dysfunction, arrhythmias, microvascular ischemia.
- Genetic mutations often in sarcomeric proteins (MYBPC3, MYH7).
Clinical Features
- May be asymptomatic or present with:
- Chest pain (often exertional)
- Palpitations
- Dyspnea on exertion
- Syncope or presyncope
- Risk of ventricular arrhythmias and sudden cardiac death (SCD) exists but is lower than septal HCM.
Electrocardiogram (ECG)
- Classic finding: Giant negative T waves in precordial leads (V3–V6).
- LVH voltage criteria may be present.
- Abnormal Q waves may occur.
Echocardiography
- Hypertrophy confined to the LV apex.
- LV cavity may appear “spade-shaped” during diastole.
Cardiac MRI
- Gold standard for confirming apical hypertrophy.
- Detects late gadolinium enhancement (fibrosis) → prognosis.
Complications
- Atrial fibrillation
- Apical aneurysm
- Ventricular arrhythmias
- SCD (less frequent than in septal HCM)
Management
- Asymptomatic: Observation, regular follow-up.
- Symptomatic: Beta-blockers or calcium channel blockers.
- Arrhythmias: Antiarrhythmics, ICD in high-risk cases.
- AF: Anticoagulation.
- Avoid competitive sports if at risk for SCD.
Prognosis
- Generally favorable prognosis.
- Risk stratification essential for arrhythmia prevention.
