rapid heartbeat
By Adam Brochert, MD
A
rapid heartbeat is defined as a heart rate that is
faster than normal. The heart normally beats fewer
than 100 times per minute in adults. In children, the
heart can beat slightly faster than 100 times per
minute and still be considered normal.
What is going on in
the body?
At rest, a person's
heart rate usually stays within a standard range.
This range is usually 50 to 100 times per minute in
adults and slightly faster in children. With
increased physical activity,
stress, or other conditions, however, the heart
rate may increase above the normal level.
What are the signs and
symptoms of the condition?
A person with a
rapid heartbeat may have no symptoms at all. When
symptoms do occur, they may include: ·
palpitations, or an unusual awareness of the
heartbeat ·
excessive sweating ·
fatigue or
weakness ·
shortness of breath ·
chest pain · lightheadedness or
dizziness ·
fainting · symptoms related to the cause of the
rapid heart rate
What are the causes
and risks of the condition?
There are many
possible causes of a rapid heartbeat, including:
· exercise, heavy lifting or other activity that
requires exertion
· fear, pain, anxiety,
stress, anger, or nervousness ·
fever ·
dehydration. This may be caused by too little
intake of fluids, loss of blood,
diarrhea,
vomiting, or medications such as diuretics,
sometimes called "water pills." ·
low blood pressure, also called hypotension ·
hyperthyroidism, which is a level of thyroid
hormone in the body that is too high ·
congestive heart failure, a condition in which
the heart cannot pump blood effectively · irregular
heartbeats, known as
arrhythmias, such as
atrial fibrillation or
ventricular tachycardia. These may be caused by
salt imbalances,
heart attack, and other conditions. · low red
blood cell count known as
anemia · medications or drugs. Albuterol, which
is commonly used to treat
asthma, as well as some over the counter and
prescription decongestants can cause rapid heartbeat.
Cocaine abuse and alcohol withdrawal are other causes
of rapid heartbeat. · excessive
caffeine intake · some herbal therapies such as
ephedra, also called ma huang · infections. These may
include such as a serious blood infection called
sepsis and
pneumonia. · nerve damage, known as
peripheral neuropathy, that affects the nerves
attached to the heart. This is often due to
diabetes, a condition that results in a high
level of blood sugar. · low oxygen in the blood, also
called hypoxia. There can be many causes for this.
Examples include
asthma and
emphysema.
Other causes are
possible. Sometimes, no cause can be found.
What can be done to
prevent the condition?
Prevention is
related to the cause. Many cases cannot be prevented.
In most people, regular exercise is advised even
though it causes a rapid heartbeat. In this case,
prevention is not an issue. Avoidance of cocaine or
alcohol can prevent cases from these drugs.
Getting enough fluids can prevent many cases due to
dehydration.
How is the condition
diagnosed?
The speed of the
heartbeat usually can be measured by checking the
pulse or listening to the heartbeat with a
stethoscope. A test that measures the electrical
activity of the heart, called an electrocardiogram or
ECG, can also be used to measure the heart rate.
Diagnosis of the
cause starts with a history and physical exam. The
healthcare provider may order tests such as:
· electrocardiogram, or
ECG, to help diagnose irregular heartbeats and
heart attacks ·
chest x-ray ·
echocardiogram, or an ultrasound of the heart, to
help diagnose congestive heart failure ·
thyroid function tests to diagnose high thyroid
levels ·
arterial blood gases to measure oxygen levels in
the blood
What are the long-term
effects of the condition?
If the heart beats
too quickly, it may not be able to pump blood well
enough to keep a person alive. Most long-term effects
are related to the cause. For example, rapid
heartbeat due to anxiety or exercise often goes away
quickly and has no long-term effects. Rapid heartbeat
due to an arrhythmia or sepsis may sometimes result
in death.
What are the risks to
others?
A rapid heartbeat
is not contagious and poses no risks to others. If
the cause of the rapid heartbeat is an infection, the
infection may be contagious.
What are the
treatments for the condition?
Treatment is
directed at the cause. For example, someone who is
dehydrated can be given fluids. A person with a fever
may be given acetaminophen. Someone with an infection
may need antibiotics or surgery. An individual with
an arrhythmia may need heart medications to slow the
heart rate, such as atenolol or lidocaine.
What are the side
effects of the treatments?
Potential side
effects depend on the treatments used. For example,
antibiotics may cause
allergic reactions or stomach upset. Surgery can
result in infection, bleeding, or
allergic reaction to the
anesthesia.
What happens after
treatment for the condition?
The heartbeat
usually returns to normal after treatment of the
cause. For example, when fever, infection, or pain
are the cause, no further treatment for the rapid
heartbeat is needed if these condition go away.
Someone with
congestive heart failure or
diabetes, however, often needs lifelong treatment
and monitoring.
How is the condition
monitored?
The speed of the
heartbeat can be monitored closely if needed. This is
done with special equipment that measures the
electrical activity in the heart. Other monitoring is
related to the cause. For example, those with a heart
attack may need close monitoring in the
intensive care unit.
