hypertrophic obstructive cardiomyopathy

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Hypertrophic cardiomyopathy is defined as the unexplained, asymmetical or concentric hypertrophy of the undilated left ventricle. There is also hypertrophy of the right ventricle.

It may be inherited as an autosomal dominant condition, but at least half of cases may be the result of sporadic mutation.

Summary points:

  • most common genetic cardiac disease (1)
    • approximate prevalence of 1:500 (2)
  • characterised by marked and asymmetric left ventricular hypertrophy, a non-dilated left ventricular cavity, diastolic impairment, generally systolic function is preserved
  • left ventricular outflow obstruction at rest caused by mitral-septal contact during systole occurs in in about 20% of patients
  • diagnostic features:
    • LV wall thickness >= 13mm on echocardiography in the absence of a well recognised. physiological cause (2)
  • in many cases patients remain asymptomatic throughout life. However in other cases patients develop heart failure or atrial fibrillation, and some die suddenly, often at a young age without previous symptoms
    • typically develops in adolescence but late onset well recognised
      • 40-50% have left ventricular outflow tract obstruction with associated systolic murmur. Symptoms include chest pain, dyspnoea, palpitations, syncope Minority at risk of SCD, stroke or heart failure (2)
  • commonest cause of sudden cardiac death in young people and athletes
  • cardioverter defibrillator is the only effective treatment for the prevention of sudden death
  • medical treatment with blockers or verapamil has been shown to improve symptoms of heart failure - however medical treatment has not been shown to modify the clinical course
  • if outflow obstruction and severe symptoms unresponsive to medical therapy represent then these patients are candidates for surgical myectomy or alcohol septal ablation to relieve the outflow obstruction
  • the minority of adult patients will develop proxysmal or chronic atrial fibrillation

Reference:

  1. BMJ 2006;332:1251-1255.
  2. Factfile (5/09).Inherited cardiovascular disease. British Heart Foundation.
  3. Factfile (5/97). Hypertrophic cardiomyopathy. British Heart Foundation.

Last reviewed 01/2018

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