Hypertrophic cardiomyopathy (HCM) is a type of cardiomyopathy and is the leading cause of sudden death (from arrhythmias) in infants, teenagers and young adults.
There is no gender predilection and has a prevalence of around 0.3 - 0.5% in the general population 4.
Hypertrophic cardiomyopathy is a genetic disorder involving the cardiac sarcomere. It is characterized by left ventricular hypertrophy (wall thickness > 12 - 15 mm) without obvious aetiology. Associated right ventricular hypertrophy may be seen in 15% of cases.
Morphologically there are several recognised sub types 4
- asymmetrical (commonest and most frequently involve the anteroseptal myocardium)
- mass like hypertrophic cardiomyopathy / tumefactive hypertrophic cardiomyopathy 8
Most common location is the basal septum. Rare apical wall hypertrophy cases reported (more in Asian groups). Concentric left ventricular wall also described. Myocardial enhancement on viability studies (MR post-gadolinium late sequences) demonstrated a worse outcome.
Can be associated with SAM (systolic anterior motion) of the anterior mitral leaflet, which can increase LVOT obstruction and decreased coronary and systemic outflow. Mitral regurgitation and left auricle dilation are some other secondary signs.
Plain film - chest radiograph
Can vary from a normal to enlarged heart.
Often shows concentric but asymmetrical hypertrophy of myocardium. May show a typical spade-like configuration on left ventricular long axis images (similar to the angiographic RAO projection) 5.
Base of treatment is to control heart rate by avoiding extreme physical effort and by drugs (e.g. Beta-blockers). In cases of family history of sudden death and obstructive sign of LVOT and/or presence of myocardial fibrosis, defibrillator device placement or alcohol arterial embolization are evaluated.
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- 7. Chun EJ, Choi SI, Jin KN et-al. Hypertrophic cardiomyopathy: assessment with MR imaging and multidetector CT. Radiographics. 2010;30 (5): 1309-28. doi:10.1148/rg.305095074 - Pubmed citation
- 8. Dillman JR, Mueller GC, Attili AK et-al. Case 153: atypical tumefactive hypertrophic cardiomyopathy. Radiology. 2010;254 (1): 310-3. doi:10.1148/radiol.2541082143 - Pubmed citation
- 9. Yamaguchi H, Ishimura T, Nishiyama S et-al. Hypertrophic nonobstructive cardiomyopathy with giant negative T waves (apical hypertrophy): ventriculographic and echocardiographic features in 30 patients. Am. J. Cardiol. 1979;44 (3): 401-12. - Pubmed citation
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Hypertrophic obstructive cardiomyopathy (HOCM)||✓|
|Hypertrophic cardiomyopathy (HCM)||✗|
|Hypertrophic non-obstructive cardiomyopathy (HNCM)||✗|