Arrhythmias

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 can stress the heart and this can contribute to the development of arrhythmias in some women. (see Cardiovascular Changes)

The significance of an arrhythmia depends on the specific type of arrhythmia and if you have an underlying heart condition. Most supraventricular arrhythmias are not life threatening. Some atrial arrhythmias (atrial fibrillation and atrial flutter) are associated with strokes and women may require blood thinners during pregnancy to protect them from stroke. Ventricular arrhythmias are more serious and can be life-threatening medical emergencies.

All women have to consider the safety of a pregnancy, taking their underlying heart condition into account. Before proceeding with trying to have a baby, it is important that you discuss your specific condition and the details of your situation with a heart specialist.

Issues for the mother

What are my risks if I develop arrhythmias?
Often very short episodes of arrhythmias are often not felt and do not affect the mother or the baby. When arrhythmias are longer, they can be uncomfortable and women may feel palpitations, dizziness, lightheadedness, chest tightness or shortness of breath. Some women with more serious arrhythmias may faint or collapse. The chance of a serious event, such as a collapse, depends on the type of arrhythmia that you have and how long it lasts.

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

Long episodes of arrhythmias, especially those associated with fainting or collapse of the mother, can have an effect on the unborn child.

Medical care during pregnancy and delivery

Where should I be followed?
If you are have arrhythmias before or during pregnancy, you should be seen by a heart specialist. Your heart specialist will determine if you need to 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 to your clinic visits, your doctors will arrange for ECG. You may need a ultrasound of the heart (medical term: echocardiogram) or an Holter monitor.

It is important that you pay attention to symptoms during your pregnancy. Notify your doctor if you develop any worrying symptoms such as palpitations, dizziness, shortness of breath, or chest tightness.

If your symptoms are concerning and you cannot get in touch with your doctor, go to your nearest emergency department. Some women may need heart rate moniting (medical term: telemetry) at the time of labour and delivery.