What Causes an Arrhythmia?
An arrhythmia can occur when the electrical signals
that control the heartbeat are delayed or blocked. This can happen when the
special nerve cells that produce the electrical signal don't work properly or
when the electrical signal doesn't travel normally through the heart. An
arrhythmia also can occur when another part of the heart starts to produce
electrical signals, adding to the signals from the special nerve cells and
disrupting the normal heartbeat.
Stress, smoking, heavy alcohol use, heavy exercise,
use of certain drugs (such as cocaine or amphetamines), use of certain
prescription or over-the-counter medicines, and too much caffeine or nicotine
can lead to arrhythmia in some people.
A
heart
attack or an underlying condition that damages the heart's electrical
system also can cause an arrhythmia. These conditions include
high
blood pressure (hypertension),
coronary
artery disease,
heart
failure, overactive or underactive thyroid gland (too much or too little
thyroid hormone produced), and rheumatic heart disease.
For some arrhythmias, such as Wolff-Parkinson-White
syndrome, the underlying heart defect that causes the arrhythmia is present at
birth (congenital). Sometimes, the cause of an arrhythmia can't be
found. |