We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
JAMA Patient Page |

Hypertrophic Cardiomyopathy FREE

Huan J. Chang, MD, MPH, Writer; Cassio Lynm, MA, Illustrator; Richard M. Glass, MD, Editor
JAMA. 2009;302(15):1720. doi:10.1001/jama.302.15.1720.
Text Size: A A A
Published online

Cardiomyopathies are diseases affecting heart muscle. In hypertrophic cardiomyopathy (HCM, aka idiopathic hypertrophic subaortic stenosis, asymmetric septal hypertrophy, hypertrophic obstructive cardiomyopathy) sarcomeres (units of heart muscle) enlarge, causing heart muscle cells to hypertrophy (increase in size). This causes the heart muscle to thicken unevenly and changes the way different parts of the heart move, which then requires it to work harder to pump blood. In HCM, hypertrophy usually involves the septum (wall) between the ventricles (lower heart chambers), which differs from other types of cardiomyopathy. As part of the hypertrophy process, the normal pattern of muscle cells is upset and can lead to problems with electrical function of the heart, resulting in arrhythmias (abnormal heartbeat). The first case of HCM was diagnosed 50 years ago. It has since been found to affect 0.2% to 0.5% of the general population and appears in all racial groups. It is the most common cause of sudden death in young people, including trained athletes, and causes heart failure disability at any age. This disorder is different from left ventricular hypertrophy, which is usually caused by undertreated hypertension. The October 21, 2009, issue of JAMA includes an article about HCM transmitted by sperm donation.


Transmisison of HCM is genetic (inherited). HCM is transmitted to 50% of individuals in each subsequent generation. It is due to a mutation in at least 1 of 11 genes coding for sarcomere protein. In persons without a family history of HCM, the most common cause is a new mutation.


Symptoms are shortness of breath, chest pain, dizziness, faintness, and palpitations. In children, the first sign of HCM is often sudden cardiac arrest (collapse and possible death) due to arrhythmias. Although it is possible to diagnose HCM through physical examination, most physicians confirm it through additional testing. The most common test is 2-dimensional echocardiography (ultrasonic waves directed at tissues), although magnetic resonance imaging (MRI) is becoming more widely used. Genetic testing using a blood test is the most sensitive diagnostic test. Other tests used in evaluating HCM include electrocardiogram (graphic tracing of electric potential caused by excitation of heart muscle) and 24-hour Holter monitor (monitor for heart rhythm).


Once HCM is identified in a person, all immediate family members should be tested as soon as possible. Medications such as beta-blockers or calcium channel blockers are the primary way to control symptoms. Other possible treatments include septal myectomy (removing a portion of the wall between the ventricles), alcohol septal ablation (destroying a portion of the wall), pacemakers, implantable defibrillators, and heart transplantation. Diuretics (water pills) should be avoided.


HCM can cause sudden death even in children and young adults, often during or just after vigorous exertion. However, others with HCM have no symptoms and live a normal lifespan. Remarkably, the first patient identified with HCM is still alive. He received a heart transplant in 1989.



To find this and previous JAMA Patient Pages, go to the Patient Page link on JAMA's Web site at http://www.jama.com. Many are available in English and Spanish. A Patient Page on implantable cardioverter-defibrillators was published in the May 2, 2007, issue.

Sources: National Institutes of Health, American Heart Association

The JAMA Patient Page is a public service of JAMA. The information and recommendations appearing on this page are appropriate in most instances, but they are not a substitute for medical diagnosis. For specific information concerning your personal medical condition, JAMA suggests that you consult your physician. This page may be photocopied noncommercially by physicians and other health care professionals to share with patients. To purchase bulk reprints, call 312/464-0776.




Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Spanish Patient Pages
Supplemental Content

Some tools below are only available to our subscribers or users with an online account.

0 Citations

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles Related By Topic
Related Collections
PubMed Articles
Case 22-2016. N Engl J Med 2016;375(3):262-72.

The Rational Clinical Examination: Evidence-Based Clinical Diagnosis
Original Article: Does This Patient Have an Abnormal Systolic Murmur?

The Rational Clinical Examination: Evidence-Based Clinical Diagnosis
Is This an Abnormal Murmur?