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Glossary of Terms


A term used to describe certain irregular heart rhythms, known as arrhythmias.

The human heart is divided into the right and left side. Each side of the heart is made up of 1) an atrium and 2) a ventricle. The atrium on each side is a receiving chamber. The right atrium receives the blood from the body after it has been used by the body's organs. The left atrium receives the newly oxygenated blood from the lungs. The atria pump the blood into their respective ventricles. The right ventricle pumps blood to the lungs, while the left ventricle pumps blood out to the body. The pumping, or contraction, of the atria and ventricles is a coordinated rhythmic motion.

Fibrillation can affect either the atria or the ventricles. With fibrillation the purposeful, coordinated and rhythmic contraction is lost. The fibrillating heart chamber produces uncoordinated movement that does not result in any useful contraction. Atrial fibrillation is not life-threatening, but can cause a decrease in blood pressure, tiredness, and is usually treatable with medication. Sometimes a small shock, known as cardioversion, is used to shock the atria back into a normal rhythm. In severe cases surgery may be performed.

Ventricular fibrillation, on the other hand, is a life-threatening arrhythmia, which requires emergency treatment. The treatment for ventricular fibrillation is medication and delivery of a counter shock, known as de-fibrillation. This de-fibrillation is what you see when the soap opera doctors shock a patient in the ER and yell "clear!"

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