Hypertrophic Cardiomyopathy With Evolution to a Mixed Hypertrophic Noncompaction Phenotype

Figures

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  Figure 1. Initial Diagnosis of HCM The patient's cardiac magnetic resonance at age 13. Severe septal hypertrophy consistent with HCM. HCM = hypertrophic cardiomyopathy.

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  Figure 2. Hypertrophic Cardiomyopathy With Marked Asymmetric Septal Hypertrophy The patient's echocardiographic images at age 19. Parasternal long- (A) and short-axis (B) views of the LV in diastole with marked septal hypertrophy, measuring 3.5 cm. A short-axis view of the LV in systole with cavity obliteration (C). Apical 4- (D) and 2-chamber (E) views. On current review of imaging, evidence of trabeculation without recesses is present (red arrows in C to E). Ao = aorta; LA = left atrium; LV = left ventricle; RA = left atrium; RV = right ventricle.

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  Figure 3. Systolic Anterior Motion of the Mitral Valve With Obstruction The patient's echocardiographic images at age 19. Parasternal long-axis (A) and apical 3-chamber (B) views in systole demonstrate septal contact of the mitral valve (red arrows). LV outflow gradient >80 mm Hg with Valsalva (C). LV = left ventricle.

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  Figure 4. Noncompaction Pathology After Septal Myectomy The patient's echocardiographic images at age 21, nearly 2 years after septal myomectomy. The parasternal long-axis view in diastole demonstrates septal myomectomy results (red arrows) with significant reduction in septal wall thickness (A). The parasternal short-axis in end-systole (B) reflects a ratio of noncompacted to compacted myocardial thickness of >2:1, with noncompacted apical lateral and anteroapical myocardium, meeting much of the primary morphologic Jenni criteria for noncompaction.1 Apical 4- (C) and 2-chamber (D) views demonstrate prominent noncompacted muscle (red arrows) with large intertrabecular recesses. Ao = aorta; LA = left atrium; LV = left ventricle.

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  Figure 5. Progressive Features of Noncompaction With Apical Thrombus The patient's echocardiogram at the time of return to care at age 25. The parasternal long-axis view in diastole demonstrates LV cavity dilatation (A). The parasternal short-axis view demonstrates persistent evidence of noncompaction pathology (B). Apical 4- (C) and 2-chamber (D) views demonstrate apical dilation with a focal apical thrombus (red arrows). Ao = aorta; LA = left atrium; LV = left ventricle; RA = left atrium; RV = right ventricle.

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  Figure 6. Complicated Features of Noncompaction With a More Extensive LV Thrombus The patient's echocardiographic images at age 28. The parasternal long-axis view in diastole with further LV cavity dilation and regression of hypertrophy (A). The parasternal short-axis view in systole with noncompaction (B). Apical 4- (C) and 2-chamber (D) views with an extensive thrombus (red arrows). Ao = aorta; LA = left atrium; LV = left ventricle.

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  Visual Summary. Case Timeline In this case, the patient was initially diagnosed with hypertrophic cardiomyopathy in adolescence. Transthoracic echocardiogram in the parasternal long-axis (A), parasternal short-axis (B), and apical 4-chamber (C) views illustrate a temporal transition to a mixed noncompaction phenotype with an evolving clinical risk. At age 19, images reflect classic features of HCM with marked septal hypertrophy (age 19: A-C). Following septal myectomy, at age 21, images demonstrate emerging features of noncompaction (age 21: A-C, noncompacted muscle identified with red arrows). At age 28, evolving features of complicated noncompaction with LV dysfunction and apical thrombus become apparent (age 28: A-C, apical thrombus identified with red arrows). Ao = aorta; LA = left atrium; LV = left ventricle.