Hypertrophic cardiomyopathy (HCM) is one of the most common genetic heart diseases. It is inherited in an autosomal dominant pattern and exhibits variable penetrance and expression. Its prevalence was initially thought to be 1:500 but could be as high as 1:200.
Hypertrophic cardiomyopathy is caused by an abnormality of heart muscle, usually caused by a genetic mutation of a sarcomeric protein, that results in disrupted myocardial alignment known as myocardial disarray. The result is regional hypertrophy with variable involvement of myocardium. Hypertrophy of the basal septum, adjacent to the left ventricular outflow tract (LVOT), may result in outflow obstruction.
Presenting symptoms are variable, and many patients remain asymptomatic for decades. When symptoms develop, they are often associated with LVOT obstruction and may include dyspnea, palpitations, syncope, or sudden cardiac death. HCM can be diagnosed at any stage of life. It is the most common cause of sudden cardiac death in young athletes.
Hypertrophic cardiomyopathy
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Synopsis
Codes
ICD10CM:
I42.2 – Other hypertrophic cardiomyopathy
SNOMEDCT:
233873004 – Hypertrophic Cardiomyopathy
I42.2 – Other hypertrophic cardiomyopathy
SNOMEDCT:
233873004 – Hypertrophic Cardiomyopathy
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Aortic stenosis – The murmur does not change with position or Valsalva; usually seen after age 50.
- Hypertensive heart disease – No murmur is noted; not usually seen in young adults; wall thickness on echocardiography is usually less than 15 mm.
- Mitral regurgitation – High-pitched holosystolic murmur best heard at the apex.
- Ventricular septal defect – Holosystolic murmur radiating all over precordium. History of congenital heart disease or myocardial infarction may be present.
- Subaortic membrane – No change in murmur with physiological maneuvers.
- Supravalvular aortic stenosis – No change in systolic murmur with physiological maneuvers; associated with Williams syndrome.
- Aortic coarctation – Higher blood pressure in upper extremities; radio-femoral delay; systolic murmur or continuous murmur may be heard.
- Cardiac amyloidosis – Low voltage on ECG; restrictive physiology is noted on echocardiography.
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Management Pearls
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.
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References
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Last Updated:07/12/2018
Hypertrophic cardiomyopathy