Arrhythmias
Alternate Names : Irregular Heartbeat
An arrhythmia of the heart is an abnormality of the rhythm or rate of the
heartbeat. The arrhythmia is caused by a disturbance of the normal electrical
activity within the heart.
What is going on in the body?
Arrhythmias can be divided into 2 main groups: tachycardias and
bradycardias. Tachycardias cause a rapid
heartbeat, with over 100 beats per minute. Bradycardias cause a slow heartbeat, with less than 60 beats per
minute. The rhythm of the heart may be regular during an arrhythmia. In other
words, each beat of the atria, or upper chambers of the heart, is followed by
one beat of the ventricles, or lower chambers of the heart. The beat may also
be irregular and may begin in an abnormal area of the heart.
What are the causes and risks of the condition?
Most arrhythmias are caused by heart
disease, including:
coronary artery disease, a
condition in which atherosclerosis, or
narrowing of the arteries, decreases the blood flow to the heart
disease of the heart valves, including infections known as endocarditis
disease of the tissue that surrounds the heart, such as bacterial pericarditis
congestive heart failure, a
disorder in which a weakened heart fails to pump enough blood to body
organs
Arrhythmias may also be caused by:
disease in the electrical system of the heart
chemicals such as adrenaline,
alcohol, or caffeine
certain prescription medications, including tricyclic antidepressants, such
as amitriptyline and
nortriptyline
certain over-the-counter medications, such as
pseudoephedrine
Arrhythmias may or may not be life threatening. In general, arrhythmias that
begin in the upper part of the heart are less dangerous than those that begin
in the lower chambers.
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