Hypertrophic Cardiomyopathy
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What is it?
An arrhythmia is an abnormal heart rhythm. There are many different types of arrhythmias. The heart beat may be too fast (medical term: tachycardia) or too slow (medical term: bradycardia). It may be regular or irregular. Arrhythmias can come from the top chambers of the heart (medical term: atria) or the bottom chambers of the heart (medical term: ventricles). (see The Normal Heart).
Different types of arrhythmias include:
- Supraventricular tachycardia or SVT – this arrhythmia usually occurs in women with normal hearts
- Atrial flutter – this arrhythmia often occurs in women with heart disease such as congenital heart disease
- Atrial fibrillation – this arrhythmia often occurs in women with heart disease such as rheumatic heart disease
- Ventricular tachycardia – this arrhythmia can occur in women with underlying heart disease or in women with a normal heart
Arrhythmias are usually detected using an ECG (medical term: electrocardiogram). They can also be detected on a Holter monitor. (see Heart Tests)
Arrhythmias during pregnancy often occur in women who had arrhythmias before pregnancy, but sometimes they occur for the first time during pregnancy. Women with an underlying heart disease are more likely to develop arrhythmias during pregnancy. Sometimes women do not feel arrhythmias. Other times, women may feel abnormal heart beats (medical term: palpitations) or they may feel dizzy or faint.
Some arrhythmias do not require treatment. Other times, arrhythmias need to be treated with medications. When arrhythmias are really fast (medical term: tachycardia) and will not stop, it may be necessary to shock the heart back into a regular rhythm (medical term: cardioversion).
How safe is it for me to become pregnant?
Pregnancy is associated with increased demands on the heart (see Cardiovascular Changes). In women with HCM, the ability to tolerate these changes is judged primarily by your ability to exercise, the strength of the heart muscle and the degree of obstruction. Most women who feel well before pregnancy do well during pregnancy.
Every pregnancy carries some risk for complications and this risk may be increased by your underlying heart disease. All women have to consider the safety of a pregnancy taking their underlying heart disease into account. Every person’s heart condition is different and therefore the safety of pregnancy differs too. Before proceeding with trying to have a baby you should discuss your specific condition and the details of your situation with a heart specialist who knows about the care of women with heart disease in pregnancy.
Issues for the mother
Which forms of birth control are safe?
Birth control (medical term: contraceptives) should be discussed with your physician. In general, most forms of contraception are fine. If you have weak heart muscle or abnormal heart rhythms (medical term: arrhythmias) then estrogen-containing contraceptives may not be suitable for you. Contraception should be discussed with a doctor who has an understanding of your underlying heart condition. (see Birth Control)
What are my risks if I become pregnant?
In order to determine your risk during pregnancy, you should see your heart specialist before getting pregnant. You may be required to have additional heart tests such as an ultrasound of your heart (medical term: echocardiogram) to better determine the risks of pregnancy.
If you felt well before pregnancy, you would be expected to do well during your pregnancy. If you have a history of symptoms before pregnancy related to your condition, there is a 30-40% risk that you will develop problems during your pregnancy. These could include chest pain, heart failure, fainting, stroke or fast heart rhythms. If your pregnancy is complicated by any of these, there is a chance that you will go into early labor. Although rare, deaths have been reported and therefore it is very important to discuss pregnancy with your heart specialist.
Some medications are not safe in pregnancy. Do not stop medications without first checking with your doctor, but do check your medications out before pregnancy so you will have a plan. If you did not do that, then do so as soon as you know you are pregnant. The MOTHERISK website is an excellent resource.
Issues for the baby
Children have a 50% risk of inheriting HCM from their parents. This condition is not always detected in young children, so your children should be checked on a regular basis, or should have genetic testing if the abnormal gene causing your own condition has been identified.
Medical care during pregnancy and delivery
Where should I be followed?
Once pregnant, you should be followed at a center that specializes in high-risk pregnancy. Your specialists will determine the frequency of follow up through your pregnancy.
What can I do and expect during pregnancy?
Your heart specialist will arrange for check up visits during your pregnancy. In addition your doctors will arrange echocardiograms to help determine how your heart is dealing with the stress of the pregnancy.
Most women with HCM do well throughout pregnancy; however, you need to pay attention to symptoms related to your heart. Notify your doctor if you develop symptoms such as chest pain, shortness of breath, swelling of the legs, fast heartbeats or fainting spells.
If your symptoms are worrying and you cannot get in touch with your doctor, go to your nearest emergency department. It is helpful to keep a letter from your doctor explaining your condition so that other health care professionals can better help you in an emergency situation.
Labour and delivery should be planned carefully with a team including a specialist in congenital heart disease, an obstetrician, an anesthetist, and a high-risk obstetrician. A vaginal delivery is usually recommended. Good pain management is important.