Apical Hypertrophic Cardiomyopathy

History: 46 year-old male with an abnormal echocardiography was referred for evaluation of cardiac structure and function. He gave no history of palpitations, dizziness or syncope.

Technique: Short and long axis FIESTA images were obtained for evaluation of cardiac morphology and function. Myocardial delayed enhancement images were acquired to look for any myocardial fibrosis.

Findings: Apical hypertrophic cardiomyopathy with a maximum end-diastolic wall thickness of 14 mm at the apex. The radial FIESTA images also confirmed the diagnosis (arrow). The MDE images showed no abnormal hyperenhancement to suggest myocardial fibrosis (lower row).

Comment: Hypertrophic cardiomyopathy (HCM) refers to abnormal thickening of the left ventricle that is not secondary to a known condition (such as AS or HTN).  The myocardial hypertrophy can be focal or diffuse.  Patients with HCM can be subdivided based on the appearance of the left ventricle. There are a number of subtypes including: 1) asymmetric septal hypertrophy, 2) concentric hypertrophy, 3) apical hypertrophy (oriental variant), and 4) mid-cavity obstruction. In some cases, hypertrophy of the septum causes obstruction in the left ventricular outflow tract.

HCM is a common endpoint for a diverse group of mutations in genes that encode for structural proteins in the heart.  Patients with HCM can be asymptomatic, can present with arrhythmias, dizziness, syncope, heart failure or sudden death.

Patients with obstructive physiology can be treated medically with beta blockers or calcium channel blockers to relieve the obstruction. If the medical therapy proves insufficient to control symptoms, these patients are candidates for surgical myectomy for relief of the obstruction. An alternative to surgery is the alcohol septal ablation technique. Patients with high risk factors for sudden cardiac death are considered for prophylactic defibrillator placement.