Arrhythmia Overview

What is an arrhythmia?

An arrhythmia is a change in the rhythm of your heartbeat. Exercise or emotions can make your heart race or skip a beat. This is usually not a cause for concern. Arrhythmias are more serious if you have other heart problems.

How does it occur?

The heart has 4 chambers. The upper chambers are called atria. The lower chambers are called ventricles. The walls of the heart contract (squeeze) to push blood through the chambers. Every normal heartbeat starts in a group of cells in the right atrium called the sinus node. These "pacemaker" cells send a regular electrical impulse to start the contraction of the heart. A normal heart rate is between 50 and 100 beats per minute.

Heart rhythm can be affected by too much alcohol or stress. The most common causes of arrhythmia are:

• a heart valve that is not working right
• coronary artery disease
• heart failure
• drugs such as cocaine
• some asthma and cold medicines
• herbs such as ephedra, guarana, and licorice.

However, arrhythmia can occur for no known reason.

What types of arrhythmia are there?

In general, types of arrhythmia that start in the ventricles are more serious than those that start in the atria. Some types of arrhythmia are:

• Atrial fibrillation: In atrial fibrillation the muscles in the atria quiver and do not contract in an organized way. They do not coordinate with the ventricles. The pulse feels very irregular and its strength changes. Atrial fibrillation can affect the ability of the heart to pump blood. It may make your heart beat fast.
• Bradycardia: In bradycardia, your heart beats very slowly. This happens when the heart's natural pacemaker (the sinus node) sets too low a heart rate or sends no signal at all to the ventricles.
• Paroxysmal supraventricular tachycardia (PSVT): Normally there is one electrical pathway between the upper and lower chambers of the heart. People with PSVT almost always have an extra electrical pathway. If the electrical signal goes down the normal pathway and then right back up the extra pathway, a "short circuit" happens. This makes the heart beat very fast.
• Ventricular tachycardia: This is a less common but dangerous kind of tachycardia. The heart beats in a regular rhythm but very fast. The heartbeat starts in the ventricles (lower heart chambers) rather than the sinus node. This abnormality is usually caused by heart disease. In a few cases it can be caused by medicine you are taking.
• Ventricular fibrillation: This is the most serious type of arrhythmia. The heart muscle quivers and is uncoordinated. The ventricles are unable to contract at all, which prevents the heart from pumping. When the heart stops beating it is called cardiac arrest. Blood flow stops. Ventricular fibrillation requires immediate medical treatment to prevent brain damage or death.

What are the symptoms?

The most common symptoms are:

• irregular heartbeat
• slow or fast heartbeat
• dizziness, lightheadedness, or fainting
• heart palpitations that feel like a sudden pounding, fluttering, or racing in the chest
• weakness
• sweatiness
• unusual lack of energy
• shortness of breath
• chest pain.

How is it diagnosed?

Your healthcare provider will ask about your symptoms and medical history. Your provider will examine your heart and lungs. You will have an electrocardiogram (ECG), which measures the electrical activity of your heart. You may have blood tests to check levels of potassium, calcium, and other minerals, and to check for diseases such as thyroid disease. You may have a chest X-ray.

Your provider may want you to wear a Holter monitor for 1 to 3 days, or to carry another type of monitor with you for several weeks. The Holter monitor is a portable ECG used to detect heart rhythm problems. If your arrhythmia seems related to exercise, you may need to have an ECG while exercising on a treadmill.

How is it treated?

If you have no symptoms, or your symptoms are fairly minor, you may not need treatment. Fast or irregular heartbeats can often be treated with medicine. If a health problem such as a leaky heart valve or heart failure is causing the arrhythmia, treating the health problem will also treat the arrhythmia. In more serious cases, other treatments are available, such as:

• An artificial pacemaker. This is an electronic device placed under the skin on the chest. It helps the heart maintain a regular beat. It is commonly used when the problem is that your heart beats too slowly.
• Implantable cardioverter-defibrillator (ICD). If you also have a weak heart muscle or have had a heart attack, your provider may recommend an ICD. ICDs detect abnormal heart rhythms and shock the heart back to a normal rhythm.
• Surgery. Ablation treatment is used to get rid of abnormal electrical pathways in the heart. This can help you have normal heart rhythms again. Arrhythmia caused by coronary artery disease may be controlled with bypass surgery.

With proper treatment, your heart will beat in a healthy rhythm, and you may resume a more normal lifestyle.

How can I take care of myself?

Carefully follow your healthcare provider's instructions for treatment.

Call your healthcare provider or 911 right away if you have any of these symptoms, especially if you have heart disease or have had a heart attack:

• chest pain
• dizziness and lightheadedness
• fainting
• shortness of breath
• a feeling of thumping, pounding, or racing in your chest or neck, or a very rapid pulse
• unexplained tiredness.

How can I help prevent arrhythmia?

The best prevention is to have a heart-healthy lifestyle. Eat a healthy diet, stay fit with the right kind of exercise for you, do not smoke, and limit your use of alcohol. If you have heart disease or high blood pressure, follow your healthcare provider's advice closely.