Noncompaction of the Ventricular Myocardium

Case Presentation: A 42-year-old woman was referred to the Hypertrophic Cardiomyopathy Clinic. A diagnosis of apical hypertrophic cardiomyopathy had been given 16 years earlier on the basis of echocardiographic findings. Left ventricular systolic function was reportedly at the lower limit of normal 5 years earlier. The patient gave a 6-month history of mild dyspnea occurring during exertion. Although still active, her exercise tolerance had decreased. She also complained of more frequent and sustained episodes of rapid palpitations associated with shortness of breath. She had occasional episodes of heavy, burning discomfort in the chest during activity and while at rest. There was no family history of cardiomyopathy, although first degree relatives had not been screened. Her heart rate was 74. Blood pressure was 110/70. Jugular venous pressure was normal. Carotid pulse volume and contour were normal. The first and second heart sounds were normal. There was a presystolic apical impulse and a prominent S4 gallop. There was no S3 gallop. A grade III/VI, harsh, midsystolic murmur was heard best at the upper left sternal border. There was no diastolic murmur. The ECG showed sinus rhythm, normal QRS duration, and left ventricular hypertrophy with repolarization changes. An echocardiogram demonstrated marked thickening and heavy trabeculation of the apical half of the left ventricle. Color Doppler displayed flow within the deep intertrabecular recesses. The left ventricle was not dilated. There was diffuse left ventricular hypokinesis with an ejection fraction of 20% to 25%. The right ventricle appeared to be more heavily trabeculated than usual. No additional abnormalities were present. The findings were consistent with isolated noncompaction of the ventricular myocardium. Noncompaction of the ventricular myocardium is a cardiomyopathy thought to be caused by arrest of normal embryogenesis of the endocardium and myocardium. This abnormality is often associated with other congenital cardiac defects, but it …