Fact-sheet: Hypertrophic cardiomyopathy
Updated on 03/28/2019 at 9:32 AM
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Definition
Primary hypertrophy of the left ventricular wall, excluding secondary hypertrophy (hypertension, aortic stenosis, systemic diseases infiltrating the myocardium).
Clinical features
Variable expression
Sometimes severe forms: sudden death, arrhythmias, heart failure
Leading cause of sudden death in young individuals
Ultrasound
First-line examination:
- confirmation of hypertrophy
- topography: asymmetric appearance is suggestive of a primary form
- effect on the LV outflow tract
- search for secondary causes: aortic stenosis
- measurement of the LV/aortic gradient
MRI
Reference examination
Cine sequences:
- myocardial hypertrophy: >15 mm at end-diastole and >13 mm if there is a family history.
- topography: asymmetric appearance highly suggestive of a primary form.
- LVEF often increased with small end-systolic volume.
- myocardial mass increased or normal if focal form.
Late gadolinium enhancement sequences: search for areas of contrast uptake indicating fibrosis.
T1 mapping sequence: prolonged T1 relaxation time of the hypertrophied myocardium in cases of fibrosis.
Signs of severity:
- hypertrophy > 30 mm.
- LV outflow tract obstruction: flow artifact related to acceleration, systolic anterior motion of the mitral valve (SAM), mitral regurgitation jet.
- diastolic dysfunction: left atrial dilation.
- foci of fibrosis.
Differential diagnosis
Secondary ventricular hypertrophy to consider in the presence of symmetric/circumferential hypertrophy:
- hypertension
- aortic stenosis.
- systemic diseases infiltrating the myocardium.
Value of T1 mapping in the initial work-up: markedly increased in amyloidosis and markedly decreased in Fabry disease.
