What is an arrhythmia?
Does having an arrhythmia mean that a person has heart disease?
What causes arrhythmias?
Are arrhythmias serious?
How common are arrhythmias?
What are the symptoms of an arrhythmia?
What happens in the heart during an arrhythmia?
What is a heart block?
What are the different types of arrhythmia?
How does the doctor know that I have arrhythmia?
What tests can be done?
How are arrhythmias treated?
How can arrhythmias be prevented?
Is research on arrhythmias being done?
An arrhythmia is a change in the regular beat of the heart. The heart may seem to skip a beat or beat irregularly or very fast or very slowly.
No, not necessarily. Many arrhythmias occur in people who do not have underlying heart disease.
Many times, there is no recognizable cause of an arrhythmia. Heart disease may cause arrhythmias. Other causes include: stress, caffeine, tobacco, alcohol, diet pills, and cough and cold medicines.
In some people, arrhythmias are associated with heart disease. In these cases, heart disease, not the arrhythmia, poses the greatest risk to the patient. In a very small number of people with serious symptoms, arrhythmias themselves are dangerous. These arrhythmias require medical treatment to keep the heartbeat regular. For example, a few people have a very slow heartbeat (bradycardia), causing them to feel lightheaded or faint. If left untreated, the heart may stop beating and these people could die.
Arrhythmias occur commonly in middle-age adults. As people get older, they are more likely to experience an arrhythmia.
Most people have felt their heart beat very fast, experienced a fluttering in their chest, or noticed that their heart skipped a beat. Almost everyone has also felt dizzy, faint, or out of breath or had chest pains at one time or another. One of the most common arrhythmias is sinus arrhythmia, the change in heart rate that can occur normally when we take a breath. These experiences may cause anxiety, but for the majority of people, they are completely harmless. You should not panic if you experience a few flutters or your heart races occasionally. But if you have questions about your heart rhythm or symptoms, check with your doctor.
Describing how the heart beats normally helps to explain what happens during an arrhythmia. The heart is a muscular pump divided into four chambers--two atria located on the top and two ventricles located on the bottom. Normally each heartbeat starts in the right atrium. Here, a specialized group of cells called the sinus node, or natural pacemaker, sends an electrical signal. The signal spreads throughout the atria to the area between the atria called the atrioventricular (AV) node. The AV node connects to a group of special pathways that conduct the signal to the ventricles below. As the signal travels through the heart, the heart contracts. First the atria contract, pumping blood into the ventricles. A fraction of a second later, the ventricles contract, sending blood throughout the body. Usually the whole heart contracts between 60 and 100 times per minute. Each contraction equals one heartbeat.
An arrhythmia may occur for one of several reasons:
Heart block is a condition in which the electrical signal cannot travel normally down the special pathways to the ventricles. For example, the signal from the atria to the ventricle may be (1) delayed, but each one conducted; (2) delayed with only some getting through; or (3) completely interrupted. If there is no conduction, the beat generally originates from the ventricles and is very slow.
There are many types of arrhythmias. Arrhythmias are identified by where they occur in the heart (atria or ventricles) and by what happens to the heart's rhythm when they occur. Arrhythmias arising in the atria are called atrial or supraventricular (above the ventricles) arrhythmias. Ventricular arrhythmias begin in the ventricles. In general, ventricular arrhythmias caused by heart disease are the most serious.
Sometimes an arrhythmia can be detected by listening to the heart with a stethoscope. However, the electrocardiogram is the most precise method for diagnosing the arrhythmia. An arrhythmia may not occur at the time of the exam even though symptoms are present at other times. In such cases, tests will be done if necessary to find out whether an arrhythmia is causing the symptoms.
First the doctor will take a medical history and do a thorough physical exam. Then one or more tests may be used to check for an arrhythmia and to decide whether it is caused by heart disease.
Many arrhythmias require no treatment whatsoever. Serious arrhythmias are treated in several ways depending on what is causing the arrhythmia. Sometimes the heart disease is treated to control the arrhythmia. Or, the arrhythmia itself may be treated using one or more of the following treatments.
There are several kinds of drugs used to treat arrhythmias. One or more drugs may be used. Drugs are carefully chosen because they can cause side effects. In some cases, they can cause arrhythmias or make arrhythmias worse. For this reason, the benefits of the drug are carefully weighed against any risks associated with taking it. It is important not to change the dose or type of your medication unless you check with your doctor first.
If you are taking drugs for an arrhythmia, one of the following tests will probably be used to see whether treatment is working: a 24-hour electrocardiogram (ECG) while you are on drug therapy, an exercise ECG, or a special technique to see how easily the arrhythmia can be caused. Blood levels of antiarrhythmic drugs may also be checked.
To quickly restore a heart to its normal rhythm, the doctor may apply an electrical shock to the chest wall. Called cardioversion, this treatment is most often used in emergency situations. After cardioversion, drugs are usually prescribed to prevent the arrhythmia from recurring.
These devices are used to correct serious ventricular arrhythmias that can lead to sudden death. The defibrillator is surgically placed inside the patient's chest. There, it monitors the heart's rhythm and quickly identifies serious arrhythmias. With an electrical shock, it immediately disrupts a deadly arrhythmia.
An artificial pacemaker can take charge of sending electrical signals to make the heart beat if the heart's natural pacemaker is not working properly or its electrical pathway is blocked. During a simple operation, this electrical device is placed under the skin. A lead extends from the device to the right side of the heart, where it is permanently anchored.
When an arrhythmia cannot be controlled by other treatments, doctors may perform surgery. After locating the heart tissue that is causing the arrhythmia, the tissue is altered or removed so that it will not produce the arrhythmia.
If heart disease is not causing the arrhythmia, the doctor may suggest that you avoid what is causing it. For example, if caffeine or alcohol is the cause, the doctor may ask you not to drink coffee, tea, colas, or alcoholic beverages.
The National Heart, Lung, and Blood Institute (NHLBI) supports basic research on normal and abnormal electrical activity in the heart to understand how arrhythmias develop. Clinical studies with patients aim to improve the diagnosis and management of different arrhythmias. These studies will someday lead to better diagnostic and treatment strategies.