There is an organization for patient support called the Hypertrophic Cardiomyopathy Association that was created by a relative of a patient who died from hypertrophic cardiomyopathy. The address is PO Box 306, Hibernia NJ 07842, the telephone number is (973) 983-7429, the email address is support@4hcm.org, and the Web site URL is http://www.4hcm.org.

There are several problems that can occur. We recommend that interested readers go to http://www.4hcm.org for more detailed information, and let us know if their site is missing something you would like to know.

• Obstruction to flow of blood out of the left ventricle to the aorta. This is an unusual type of obstruction in that it occurs only while the left ventricle is contracting and only when the portion of the septum near the aortic valve is thickened. To understand why obstruction occurs, it is important to understand that one of the leaflets that make up the mitral valve lies close to the septum when the mitral valve is open. When the left ventricle begins to contract, blood starts to flow between the opened mitral leaflet and the septum into the aortic valve, which lies between them. This flow of blood draws the mitral valve leaflet closer to the septum, which makes it harder for the blood to flow. This is called dynamic obstruction.

  Diagnosis of obstructive hypertropic cardiomyopathy can be made by echocardiography and by left heart catheterization.

  Treatments for obstructive hypertrophic cardiomyopathy include medications that are negative inotropic agents, such as beta-blockers and verapamil, avoidance of positive inotropes such as digitalis compounds, implantation of a dual chamber pacemaker, replacement of the mitral valve (to eliminate the leaflet that obstructs the passage of blood flow), and surgical or chemical resection of the thickened part of the septum. Each of these options has advantages and disadvantages, and should be discussed with your doctor.

• Heart failure "Heart failure" in this setting refers to shortness of breath and/or weakness due to inability of the heart to pump enough blood to empty the lungs and supply the body with oxygenated blood. Unlike congestive heart failure, heart failure in hypertrophic cardiomyopathy is due to "diastolic dysfunction", which means that the heart muscle does relax fast enough and completely enough to allow blood to flow in before the heart begins to contract again.

  If obstruction to flow is present, the treatments are as above. If there is no obstruction, only the medications described above are used.

• Fast heart rhythms such as ventricular tachycardia. Unfortunately, the cellular structure of the heart muscle in hypertrophic cardiomyopathy is not normal. Perhaps for this reason, people with this condition are at risk for sudden death due to ventricular tachcardia and ventricular fibrillation.

  There are no good diagnostic tests for identifying the few people with this condition who will die suddenly. Electrophysiological study has been reported to be helpful by some physicians but not all. For this reason, electrophysiologists look for clues in a person's history that suggest a higher risk: family history of sudden death with hypertrophic cardiomyopathy, syncope (passing out spells) or near-syncope, and the finding of ventricular tachycardia on ambulatory ("Holter") electrocardiography recordings.

  Until relatively recently, there were no good treatments for patients with hypertrophic cardiomyopathy who were at high risk for sudden death. At this time, most such patients are treated with implantable cardioverter-defibrillators (ICDs), which are quite safe and very effective.