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The human heart usually beats with a regular rhythm at a predictable rate. But sometimes the rhythm and rate will change. There are a variety of reasons that this happens. The condition is called arrhythmia (ah-RITH-me-uh).
An arrhythmia is a heartbeat that is not normal. It is also called abnormal or irregular.
Sometimes arrhythmia has no symptoms. In other cases, it causes upsetting and sometimes life-threatening conditions. To understand arrhythmia, you need to learn how the heart works.
Your heart is a muscular organ that is about the size of your fist. It sits in the left side of your chest. Its job is to pump oxygen-rich blood all through the body. As tissues in the body use oxygen, they return wastes in the form of carbon dioxide to the blood. These wastes are carried to the lungs and exhaled.
Your heart pumps nearly 5 quarts of oxygen-rich blood through your body every minute. The heart’s 4 chambers work together to pump the blood. The two upper chambers are called atria (AY-tree-uh), and the two lower chambers are called ventricles (VEN-truh-coals).
To do its pumping work, your heart uses a network of electrical pathways, similar to the electric wiring in your home. This electrical system passes signals from one part of the heart to another, which makes the heart beat regularly.
The heart’s electrical signals begin with a natural pacemaker called the S-A (sinoatrial) node. The S-A node is located in the heart’s upper right chamber. The specialized cells in this pacemaker send an electrical impulse from the S-A node down to the next part of the electrical system, the A-V (atrio-ventricular) node.
The A-V node serves as the bridge between the upper and lower chambers of the heart. It sends on the electrical impulse to the bundle branches, which are located inside the right and left ventricles. The electrical signal causes both the right and left ventricles to tighten or contract, then relax.
This network of signals is called the electrical conduction system. It involves passing (or conducting) the electrical current down the heart muscle to produce a strong, regular, and healthy heart contraction. The result is a single heartbeat, which occurs over and over again to pump blood all through the body.
The cardiac conduction system speeds up your heart rate as you climb stairs, for example. As a result, your heart pumps faster and your body gets more oxygen-rich blood. The conduction system also slows down the heart rate as you sleep.
Any disease or abnormality along this electrical pathway can result in an abnormal heart rate. The normal resting heart rate is between 60 and 100 beats per minute. Sometimes your heart’s natural rhythm becomes too slow, too fast, or irregular. When you have arrhythmia, your heart may not deliver enough oxygen-rich blood to your body.
Some irregular heartbeats are common and usually harmless, such as when it happens just once in a while or without any other symptoms. It is not uncommon for a person to feel an occasional “missed beat.” It is also normal for someone to have a faster heart rate when excited or exercising.
However, when these irregularities happen over and over again, it is important to check with your doctor. Some of the signs and symptoms of arrhythmia include:
A heart rhythm that is too slow is called bradycardia (bray-dee-CAR-dee-uh). This happens when the system that sends messages to contract the heart muscle does not work properly. Sometimes the message is not sent. In other cases, the message is sent but blocked, or takes another route. The result is a heart rate that is too slow. Your body does not get the oxygen and blood that it needs to work properly.
There are several types of bradycardia:
A heart rate that is too fast is called tachycardia (tack-ee-CAR-dee-uh). Sometimes the electrical signals are sent so quickly and irregularly that they cause the heart muscle to tremble or quiver. The resulting beat is not strong enough to pump blood correctly. This leads to a condition called fibrillation (fib-ril-AY-shun).
There are a number of conditions that result from a fast or quivering heartbeat:
There can be several reasons why arrhythmia occurs. In some cases, a medical condition such as high blood pressure or coronary artery disease can be the cause. In other cases, caffeine, smoking, or certain medicines (prescription and nonprescription) can be the cause.
If your doctor thinks you might have arrhythmia, he or she will do a complete medical history and physical exam. The doctor also may order any of the following tests:
There are a number of ways to treat an irregular heart beat. Treatment depends on the type and seriousness of the irregularity. It also is affected by the patient’s age, general physical condition, and medical history. Treatment may include any of the following:
If arrhythmia is caused by coronary artery disease, this condition must first be treated with medicine, surgery, or special medical procedures. These can include:
In addition, further coronary artery disease may be prevented through the following self-help approaches:
Many times, arrhythmia can be successfully treated with a medical or surgical treatment plan. It is very important to call your doctor if you have any symptoms of