HYPERTROPHIC CARDIOMYOPATHY
Hypertrophic cardiomyopathy is a heart disease characterized by increased thickness of the heart muscle. At the
same time, the muscle cells themselves are unorganized or in disarray. This disease occurs in some fashion in
approximately 1 out of 500 individuals. In many instances it is unrecognized and without any symptoms. It
may, however, cause symptoms such as shortness of breath, chest pain and fainting. It can infrequently be a
cause of sudden cardiac death. The chance of dying suddenly from this disease is approximately 1% per year,
which is about the same as the general rate for all adults. There are some patients who are at higher risk for
sudden death and their death rate is 6% per year. Hypertrophic cardiomyopathy is an inherited disease.
If you are reading this, you have probably already been diagnosed as having hypertrophic heart disease or know
a friend or family member that has the diagnosis. Because it is an inherited disease, all of the close relatives
such as brothers, sisters and children should be evaluated to see if they also have hypertrophic cardiomyopathy.
It would not be unreasonable to also screen the parents of younger individuals with the diagnosis in the event
that they too may have unrecognized cardiomyopathy. The patient should be considered for testing for his/her
DNA to see if there are any abnormalities in his/her chromosomes. If these abnormalities are found it becomes
easier to screen other family members for the same abnormalities.
If DNA is not available, there are these screening suggestions:
1. Patients aged 12-18 years old – screen on an annual basis with:
A. History and physical.
B. 12-lead EKG.
C. Echocardiogram.
2. If the patient is older than 18 years:
A. Perform initial screening with history and physical, EKG and echocardiogram and, if negative, repeat
every five years.
3. Patients discovered on above screening to have hypertrophic obstructive cardiomyopathy should be
reevaluated every 12-18 months.
Those patients with a diagnosis of hypertrophic cardiomyopathy should be seen on an annual basis
(especially if younger than 60 years old). This followup would include:
1. History and physical, and family history.
2. 2D echocardiogram.
3. 24- or 48-hour Holter monitor.
4. Evaluation of blood pressure response during stress testing.
The treatment of hypertrophic cardiomyopathy has two major approaches:
1.
Improvement in symptoms.
The most common symptoms are shortness of breath, chest pain and fainting. The majority of medications
utilized are beneficial for symptoms by reducing the heart rate so the heart has time to fill with blood more
adequately. Some patients with hypertrophic heart disease also have obstruction or thickening of the muscle just
as the blood leaves the heart. These types have patients have hypertrophic obstructive cardiomyopathy.
Medications also reduce the strength of this thickened area and prevent the blood flow from being obstructed. In
those patients in whom medication is not adequate to control symptoms, certain surgical modalities can be
utilized. The most successful is surgery to remove part of the thickened muscle tissue that causes obstruction.
Another approach would be to inject alcohol directly into the thick muscle. Alcohol will kill the tissue and leave
a scarred area which does not contract or cause an obstruction. Finally, pacemakers are an option but have not
DCC, December 2007
been proven to be used routinely. They may be of some benefit in older individuals who could not tolerate
surgery.
2.
Prevention of sudden death
The biggest concern in hypertrophic cardiomyopathy is the potential of sudden cardiac death caused by an
abnormal heart rhythm. This may occur in individuals who have not had symptoms before. It has also occurred
in individuals that have been performing extremely competitive sports. In general, most patients would
reasonably be very concerned about the possibility of sudden death. It is important to recognize however that
sudden death is infrequent and should not be a focal point that it destroys the patient’s emotional being or
quality of life. Most individuals with this diagnosis are able to lead normal lives in relationship to their
occupation, recreational activities and social life. Women are generally able to become pregnant and deliver
healthy babies with a normal labor. Since there are reports of sudden death with competitive activity, all
patients with this diagnosis should avoid extremely competitive or very strenuous physical activity and heavy
weight-lifting.
There are some adult patients who are at low risk for sudden cardiac death. This includes those who have:
 No or only mild chest pain or exertional dyspnea.
 Absence of a family history for premature death from hypertrophic cardiomyopathy.
 Absence of fainting which was felt to be related to hypertrophic cardiomyopathy.
 Absence of serious heart rhythm problems during a Holter monitor.
 An outflow gradient or pressure drop of less than 30 mm on echocardiogram.
 Normal or minimal increase in the size of the left atrium on echo, i.e., less than 45 mm.
 Normal blood pressure response to upright stress.
 Mild left ventricular hypertrophy (wall thickness less than 20 mm on echo).
Factors that indicate a high risk for sudden cardiac death:
 Prior cardiac arrest or spontaneously-occurring and sustained dangerous heart rhythm abnormalities.
 Family history of premature cardiac death related to cardiomyopathy, particularly if sudden in a close
relative or if multiple in occurrence.
 Identification of a high-risk mutant gene on DNA analysis.
 Unexplained fainting, particularly in young patients when it occurs with exertion or recurs.
 Abnormal heart rhythm discovered on Holter monitoring.
 Abnormal drop in blood pressure during stress testing.
 Extreme thickness of the heart muscle (greater than 30 mm on echo).
Prevention of sudden cardiac death needs to be discussed with your physician. One medication, amiodarone,
may be beneficial in reducing sudden cardiac death. Unfortunately, there are multiple side effects with this
medication that may be bothersome. There are no documented studies of medications that are highly
recommended. The most successful approach to prevent sudden death has been the implantation of a pacemaker
device called an automatic internal cardiac defibrillator (AICD). The more risk factors for sudden cardiac death
that are present, the more important it would be to insert a defibrillator. If a patient develops a life-threatening
arrhythmia the AICD will fire and “shock” the rhythm back to normal. This would be like a life-saving
insurance policy. On the other hand, most patients with only minor risk factors that are older or have other
major disease issues may not wish the cost, surgical risk or long-term consequences of a defibrillator.
DCC, December 2007