Heart Arrhythmia - Rhythm Disorders

Heart Arrhythmia - Rhythm Disorders 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.

Does having an arrhythmia mean that a person has heart disease?
No, not necessarily. Many arrhythmias occur in people who do not have underlying heart disease.

What causes arrhythmias?
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.

Are arrhythmias serious?
The vast majority of people with arrhythmias have nothing to fear. They do not need extensive exams or special treatments for their condition.

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.

How common are arrhythmias?
Arrhythmias occur commonly in middle-age adults. As people get older, they are more likely to experience an arrhythmia.

What are the symptoms of 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.

Arrhythmia Types
Originating in the Atria:

Originating in the Ventricles:

What happens in the heart during an arrhythmia?
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:

What is a heart block?
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.

What are the different types of an arrhythmias?
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.

How does the doctor know that I have arrhythmia?
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.

What tests can be done?
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.

Tests for Detecting Arrhythmias:

How are arrhythmias treated?
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.

How can arrhythmias be prevented?
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.

Is research on arrhythmias being done?
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.

Source: The National Heart, Lung, and Blood Institute



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