Topic Overview
Your
heart normally beats in a regular rhythm and rate that is just right for the
work your body is doing at any moment. The usual resting heart rate for adults
is between 50 to 100 beats per minute. Children have naturally higher normal
heart rates than adults.
The
is a pump made up of
: two upper chambers (atria) and two lower chambers
(ventricles). It is powered by an
that puts out pulses in a regular
rhythm. These pulses keep the heart pumping and keep blood flowing to the lungs
and body.
When the heart beats too fast, too slow, or with a
skipping (irregular) rhythm, a person is said to have an
. A change in the heart's rhythm may feel
like an extra-strong heartbeat () or a fluttering in your
chest. Premature ventricular contractions (PVCs) often cause this feeling.
A heartbeat that is occasionally irregular usually is not a concern if
it does not cause other symptoms, such as dizziness,
, or shortness of breath. It is not
uncommon for children to have extra heartbeats. In healthy children, an extra
heartbeat is not a cause for concern.
When heart rate or rhythm changes are minor
Many
changes in heart rate or rhythm are minor and do not require medical treatment
if you do not have other symptoms or a history of heart disease. Smoking,
drinking alcohol or caffeine, or taking other stimulants such as diet pills or
cough and cold medicines may cause your heart to beat faster or skip a beat.
Your heart rate or rhythm can change when you are under stress or having pain.
Your heart may beat faster when you have an illness or a fever. Hard physical
exercise usually increases your heart rate, which can sometimes cause changes
in your heart rhythm.
Dietary supplements, such as goldenseal,
oleander, motherwort, or ephedra (also called ma huang), may cause irregular
heartbeats.
It is not uncommon for pregnant women to have minor
heart rate or rhythm changes. These changes usually are not a cause for concern
for women who do not have a history of heart disease.
Well-trained
athletes usually have slow heart rates with occasional pauses in the normal
rhythm. Evaluation is usually not needed unless other symptoms are present,
such as lightheadedness or fainting (), or
there is a family history of heart problems.
When heart rate or rhythm changes are more serious
Irregular heartbeats change the amount of blood that flows to the lungs
and other parts of the body. The amount of blood that the heart pumps may be
decreased when the heart pumps too slow or too fast.
Changes such
as
that start in the upper chambers
of the heart can be serious, because they increase your risk of forming blood
clots in your heart. This in turn can increase your risk for having a stroke or
a blood clot in your lungs (). People who have
,
, or a history of heart attack should be
more concerned with any changes in their usual heart rhythm or rate.
Fast heart rhythms that begin in the lower chambers of the heart are
called ventricular arrhythmias. They usually are fast and regular, such as
ventricular tachycardia, or fast and irregular, such as ventricular
fibrillation. These types of heart rhythms make it hard for the heart to
pump enough blood to the brain or the rest of the body and can be
life-threatening. Ventricular arrhythmias may be caused by heart disease such
as heart valve problems, impaired blood flow to the heart muscle (ischemia or a
heart attack), a weakened heart muscle (cardiomyopathy), or heart
failure.
Ventricular tachycardia is a life-threatening arrhythmia
that can quickly lead to ventricular fibrillation, which causes death if not
treated. Both usually cause fainting (syncope) within seconds, and you may have
. Emergency medical
treatment is needed, such as medicines and electrical shock
(defibrillation).
When you have a change in your heart rhythm or
rate, you also may have other symptoms, such as chest pain, shortness of
breath, lightheadedness, fainting, confusion, or weakness. Changes in your
heart rate or rhythm with other symptoms can be caused by a serious heart
problem.
Taking illegal drugs (such as stimulants, like cocaine or methamphetamine)
or misusing prescription and nonprescription
can cause serious heart rhythm or rate
changes and may be life-threatening.
The U.S. Food and Drug
Administration (FDA) has banned the sale of ephedra, a stimulant sold for
weight loss and sports performance, because of concerns about safety. Ephedra
has been linked to
,
, and some sudden deaths.
Check your symptoms to decide if and when
you should see a doctor.